Bug 118644 Hint for Date Time Parameters
The hint you give for date time parameters (Please enter date ... pattern: MM/DD/YYYY ....) is only true if the date is unformatted. If you apply a format, you must enter it according to it. So it's quite confusing!
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
{
			String pattern = formatPattern;
			if ( formatPattern == null )
			{
				if ( DesignChoiceConstants.STRING_FORMAT_TYPE_CUSTOM.equals( formatCategroy )
						|| DesignChoiceConstants.DATETIEM_FORMAT_TYPE_CUSTOM.equals( formatCategroy )
						|| DesignChoiceConstants.NUMBER_FORMAT_TYPE_CUSTOM.equals( formatCategroy ) )
				{
					return string;
				}
				pattern = formatCategroy;
			}
			if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
			{
				DateFormatter formatter = new DateFormatter( STANDARD_DATE_TIME_PATTERN );
				Date date = formatter.parse( string );
				formatter.applyPattern( pattern );
				string = formatter.format( date );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( getSelectedDataType( ) ) )
			{
				string = new NumberFormatter( pattern ).format( DataTypeUtil.toDouble( string )
						.doubleValue( ) );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( getSelectedDataType( ) ) )
			{
				string = new NumberFormatter( pattern ).format( DataTypeUtil.toBigDecimal( string ) );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_STRING.equals( getSelectedDataType( ) ) )
			{