sub ValidateInput
	{
	my ($eDirection);
	if ($#_ != 0)
		{
		$eDirection = $::FORWARD;
		}
	($eDirection) = @_;
	my ($bActuallyValidate) = ($eDirection == $::FORWARD);	# only validate text when moving forward
	my (@Response);

	#Modification to handle null error problem
	#
	# special case - startup
	#
	if ($::g_nCurrentSequenceNumber == $::STARTSEQUENCE) # if this is startup
		{
		@Response = ValidateStart($bActuallyValidate); # validate the input/cart settings
		if ($::g_NullInput)
			{
			my $sError = '<B><SPAN CLASS="actrequiredcolor">No data has been received.' .
				"<br>This may be due to an internet communications error." .
				"<br>Please try to submit the form again.</SPAN></B>" .
				"<img src='null_error.gif' height=1 width=1>";
			@Response = DisplayPage($sError, 0, $eDirection);	# redisplay this page with the error messages
			if ($Response[0] != $::SUCCESS)
				{
				return (@Response);
				}
			$Response[0] = $::BADDATA;
			$Response[1] = $Response[2];
			$Response[2] = $Response[3];
			}
		return (@Response);
		}
	else