Modified MSSQL driver to use mssql_get_last_message() for error messages.
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index 4748d56..97ac971 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -438,8 +438,7 @@
 	 */
 	function _error_message()
 	{
-		// Are errros even supported in MS SQL?
-		return '';
+		return mssql_get_last_message();
 	}
 	
 	// --------------------------------------------------------------------