diff --git a/Classes/PHPExcel/Calculation/DateTime.php b/Classes/PHPExcel/Calculation/DateTime.php
index 9e7257e..59aae40 100644
--- a/Classes/PHPExcel/Calculation/DateTime.php
+++ b/Classes/PHPExcel/Calculation/DateTime.php
@@ -549,6 +549,8 @@ class PHPExcel_Calculation_DateTime {
 					if ($retVal < 0) { $retVal += 365; }
 				}
 				break;
+			default:
+				$retVal = PHPExcel_Calculation_Functions::NaN();
 		}
 		return $retVal;
 	}	//	function DATEDIF()
@@ -753,7 +755,7 @@ class PHPExcel_Calculation_DateTime {
 	public static function WORKDAY($startDate,$endDays) {
 		//	Retrieve the mandatory start date and days that are referenced in the function definition
 		$startDate	= PHPExcel_Calculation_Functions::flattenSingleValue($startDate);
-		$endDays	= (int) PHPExcel_Calculation_Functions::flattenSingleValue($endDays);
+		$endDays	= PHPExcel_Calculation_Functions::flattenSingleValue($endDays);
 		//	Flush the mandatory start date and days that are referenced in the function definition, and get the optional days
 		$dateArgs = PHPExcel_Calculation_Functions::flattenArray(func_get_args());
 		array_shift($dateArgs);
@@ -763,6 +765,7 @@ class PHPExcel_Calculation_DateTime {
 			return PHPExcel_Calculation_Functions::VALUE();
 		}
 		$startDate = (float) floor($startDate);
+		$endDays = (int) floor($endDays);
 		//	If endDays is 0, we always return startDate
 		if ($endDays == 0) { return $startDate; }
 
diff --git a/Classes/PHPExcel/Calculation/Functions.php b/Classes/PHPExcel/Calculation/Functions.php
index 22cb633..2e80b83 100644
--- a/Classes/PHPExcel/Calculation/Functions.php
+++ b/Classes/PHPExcel/Calculation/Functions.php
@@ -750,6 +750,12 @@ if (!function_exists('money_format')) {
 		}
 		$space = $locale["{$letter}_sep_by_space"] ? ' ' : '';
 
+		if (!isset($locale['mon_decimal_point']) || empty($locale['mon_decimal_point'])) {
+			$locale['mon_decimal_point'] = (!isset($locale['decimal_point']) || empty($locale['decimal_point'])) ?
+											$locale['decimal_point'] :
+											'.';
+		}
+
 		$number = number_format($number, $right, $locale['mon_decimal_point'], $flags['nogroup'] ? '' : $locale['mon_thousands_sep'] );
 		$number = explode($locale['mon_decimal_point'], $number);
 
diff --git a/Classes/PHPExcel/Calculation/MathTrig.php b/Classes/PHPExcel/Calculation/MathTrig.php
index a2a4ae7..a3fd92e 100644
--- a/Classes/PHPExcel/Calculation/MathTrig.php
+++ b/Classes/PHPExcel/Calculation/MathTrig.php
@@ -798,11 +798,12 @@ class PHPExcel_Calculation_MathTrig {
 
 
 	public static function ROMAN($aValue, $style=0) {
-		$aValue	= (integer) PHPExcel_Calculation_Functions::flattenSingleValue($aValue);
+		$aValue	= PHPExcel_Calculation_Functions::flattenSingleValue($aValue);
 		$style	= (is_null($style))	? 0 :	(integer) PHPExcel_Calculation_Functions::flattenSingleValue($style);
 		if ((!is_numeric($aValue)) || ($aValue < 0) || ($aValue >= 4000)) {
 			return PHPExcel_Calculation_Functions::VALUE();
 		}
+		$aValue = (integer) $aValue;
 		if ($aValue == 0) {
 			return '';
 		}
@@ -839,7 +840,7 @@ class PHPExcel_Calculation_MathTrig {
 		$digits	= PHPExcel_Calculation_Functions::flattenSingleValue($digits);
 
 		if ((is_numeric($number)) && (is_numeric($digits))) {
-			$significance = pow(10,$digits);
+			$significance = pow(10,(int) $digits);
 			if ($number < 0.0) {
 				return floor($number * $significance) / $significance;
 			} else {
@@ -864,7 +865,7 @@ class PHPExcel_Calculation_MathTrig {
 		$digits	= PHPExcel_Calculation_Functions::flattenSingleValue($digits);
 
 		if ((is_numeric($number)) && (is_numeric($digits))) {
-			$significance = pow(10,$digits);
+			$significance = pow(10,(int) $digits);
 			if ($number < 0.0) {
 				return ceil($number * $significance) / $significance;
 			} else {
diff --git a/Classes/PHPExcel/Calculation/TextData.php b/Classes/PHPExcel/Calculation/TextData.php
index 2e676fc..d23bf9c 100644
--- a/Classes/PHPExcel/Calculation/TextData.php
+++ b/Classes/PHPExcel/Calculation/TextData.php
@@ -96,7 +96,7 @@ class PHPExcel_Calculation_TextData {
 		$stringValue	= PHPExcel_Calculation_Functions::flattenSingleValue($stringValue);
 
 		if (is_bool($stringValue)) {
-			$stringValue = ($stringValue) ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE();
+			return ($stringValue) ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE();
 		}
 
 		if (self::$_invalidChars == Null) {
@@ -106,7 +106,7 @@ class PHPExcel_Calculation_TextData {
 		if (is_string($stringValue) || is_numeric($stringValue)) {
 			return str_replace(self::$_invalidChars,'',trim($stringValue,"\x00..\x1F"));
 		}
-		return Null;
+		return NULL;
 	}	//	function TRIMNONPRINTABLE()
 
 
@@ -119,10 +119,14 @@ class PHPExcel_Calculation_TextData {
 	public static function TRIMSPACES($stringValue = '') {
 		$stringValue	= PHPExcel_Calculation_Functions::flattenSingleValue($stringValue);
 
-		if (is_string($stringValue) || is_numeric($stringValue)) {
-			return trim(preg_replace('/  +/',' ',$stringValue));
+		if (is_bool($stringValue)) {
+			return ($stringValue) ? PHPExcel_Calculation::getTRUE() : PHPExcel_Calculation::getFALSE();
 		}
-		return Null;
+
+		if (is_string($stringValue) || is_numeric($stringValue)) {
+			return trim(preg_replace('/ +/',' ',trim($stringValue,' ')));
+		}
+		return NULL;
 	}	//	function TRIMSPACES()
 
 
@@ -133,6 +137,8 @@ class PHPExcel_Calculation_TextData {
 	 * @return	int
 	 */
 	public static function ASCIICODE($characters) {
+		if (($characters === NULL) || ($characters === ''))
+			return PHPExcel_Calculation_Functions::VALUE();
 		$characters	= PHPExcel_Calculation_Functions::flattenSingleValue($characters);
 		if (is_bool($characters)) {
 			if (PHPExcel_Calculation_Functions::getCompatibilityMode() == PHPExcel_Calculation_Functions::COMPATIBILITY_OPENOFFICE) {
@@ -287,10 +293,16 @@ class PHPExcel_Calculation_TextData {
 	 *	@param	mixed	$value	Value to check
 	 *	@return	boolean
 	 */
-	public static function FIXEDFORMAT($value,$decimals=2,$no_commas=false) {
+	public static function FIXEDFORMAT($value, $decimals = 2, $no_commas = FALSE) {
 		$value		= PHPExcel_Calculation_Functions::flattenSingleValue($value);
 		$decimals	= PHPExcel_Calculation_Functions::flattenSingleValue($decimals);
-		$no_commas		= PHPExcel_Calculation_Functions::flattenSingleValue($no_commas);
+		$no_commas	= PHPExcel_Calculation_Functions::flattenSingleValue($no_commas);
+
+		// Validate parameters
+		if (!is_numeric($value) || !is_numeric($decimals)) {
+			return PHPExcel_Calculation_Functions::NaN();
+		}
+		$decimals = floor($decimals);
 
 		$valueResult = round($value,$decimals);
 		if ($decimals < 0) { $decimals = 0; }
@@ -540,7 +552,7 @@ class PHPExcel_Calculation_TextData {
 			}
 		}
 
-		return $left.$newText.$right;
+		return $text;
 	}	//	function SUBSTITUTE()
 
 
diff --git a/Classes/PHPExcel/Shared/Date.php b/Classes/PHPExcel/Shared/Date.php
index 111b479..41085b6 100644
--- a/Classes/PHPExcel/Shared/Date.php
+++ b/Classes/PHPExcel/Shared/Date.php
@@ -40,6 +40,20 @@ class PHPExcel_Shared_Date
 	const CALENDAR_WINDOWS_1900 = 1900;		//	Base date of 1st Jan 1900 = 1.0
 	const CALENDAR_MAC_1904 = 1904;			//	Base date of 2nd Jan 1904 = 1.0
 
+	public static $_monthNames = array(	'Jan' => 'January',
+										'Feb' => 'February',
+										'Mar' => 'March',
+										'Apr' => 'April',
+										'May' => 'May',
+										'Jun' => 'June',
+										'Jul' => 'July',
+										'Aug' => 'August',
+										'Sep' => 'September',
+										'Oct' => 'October',
+										'Nov' => 'November',
+										'Dec' => 'December'
+									  );
+
 	private static $ExcelBaseDate	= self::CALENDAR_WINDOWS_1900;
 
 	public static $dateTimeObjectType	= 'DateTime';