Ok, that was easy... you do not tell the script what $date2 should be. So I simply added the line above "&calcdifference" to your code and it works:

	for ($a = 0; $a < @messages; $a++) {
		($id, $dummy, $dummy, $dummy, $date1) = split(/\|/, $messages[$a]);
		$date2 = $date;
		&calcdifference; 

I wonder how the code in your board knows that it should use $date for $date2 without having that line?

But I now added the following line to my &calcdifference sub:

	if ($date2 eq "") { $date2 = $date; } 

Perhaps the original sub uses similar code and so it works for you.

It's very good for a first mod! I couldn't do it, I guess. I did many mods on my forum, but I always have to compare to existing code and sometimes puzzle my code together taking a code part from here and a code part from there... it's like building a new car out of 10 old ones  .

Yes, same here. And I think understanding existing perl code and using the parts you want to use in your own new mod isn't easy at all. So I would say we both are no master coders but it's enough for the one or other cool mod  .

By the way, here's the sub that would need to be altered to work with your mod... it's from my ModifyMessage.pl and part of the multidel mod. But since I may have altered the code it's better if you have a look at that code instead of the original code.

No haste - if you find time .

sub MultiDel {
	$yySetLocation = qq~$cgi;action=display;num=$INFO{'thread'};start=$INFO{'start'}~;
	$mkill = 0;
	$topickill = 0;
	fopen(FILE, "$datadir/$INFO{'thread'}.txt", 1) || &fatal_error("$txt{'23'} $INFO{'thread'}.txt");
		@mess = <FILE>;
	fclose(FILE);
	$count = $#mess;
	$tnum = $INFO{'thread'};

	fopen(AMV, "$vardir/attachments.txt");
		my @attachments = <AMV>;
	fclose(AMV);

	# Find thread position in message index
	fopen(FILE, "$boardsdir/$currentboard.txt");
		@threads = <FILE>;
	fclose(FILE);
	$tmpcount = 0;
	$threadpos = '';
	foreach $curentry (@threads) {
		($tmpa, $dummy) = split(/\|/, $curentry);
		if($INFO{'thread'} eq $tmpa) { $threadpos = $tmpcount; }
		$tmpcount++;
	}

	# check all checkboxes, delete posts if checkbox is ticked
	while (0 <= $count) {
		if ($FORM{"del$count"} ne '' && $threadpos ne ''){
			($msub, $mname, $memail, $mdate, $musername, $micon, $mattach, $mip, $mmessage, $mns, $mlm, $mlmb, $msf, $mfn) = split( /\|/, $mess[$count] );
			chomp $mfn;
			if(-e("$upload_dir/$mfn")) {
				$attachpos = $#attachments;
				while (0 <= $attachpos) {
					my ($amthreadid, $amreplies, $amthreadsub, $amposter, $amcurrentboard, $amkb, $amdate, $amfn) = split(/\|/,$attachments[$attachpos]);
					chomp $amfn;
					if($tnum eq $amthreadid) {
						if($amreplies eq $count) {
							splice(@attachments, $attachpos, 1);
						} elsif ($amreplies > $count) {
							$amreplies--;
							$attachments[$attachpos] = \n";
						}
					}
					$attachpos--;
				}
				unlink("$upload_dir/$mfn");
			}

			if ($mess[1] eq '' || $mess[1] eq "\n"){
				# if this is the only post, delete the files
				unlink("$datadir/$tnum.txt");
				unlink("$datadir/$tnum.mail");
				unlink("$datadir/$tnum.data");
				unlink("$datadir/$tnum.poll");
				unlink("$datadir/$tnum.polled");
				unlink("$datadir/$tnum.polll");
				splice(@threads, $threadpos, 1);
				$topickill = 1;
				$yySetLocation = qq~$cgi~;
			} else {
				# if this is not the only post, delete post
				splice(@mess, $count, 1);
				$mkill++;
			}
		}
		$count--;
	}

	# if thread has not been deleted from message index, update message index details
	($msub, $mname, $memail, $mdate, $musername, $micon, $mattach, $mip, $mmessage, $mns, $mlm, $mlmb) = split( /\|/, $mess[$#mess]);

	if ($topickill != 1 && $threadpos ne ''){
		($tnum, $tsub, $tname, $temail, $tdate, $treplies, $tusername, $ticon, $tstate) = split( /\|/, $threads[$threadpos] );
		$treplies = $treplies - $mkill;
		$threads[$threadpos] = qq~$tnum|$tsub|$tname|$temail|$mdate|$treplies|$tusername|$ticon|$tstate~;

		# Save updated posts
		fopen(FILE, ">$datadir/$INFO{'thread'}.txt", 1) || &fatal_error("$txt{'23'} $threadid.txt");
			print FILE @mess;
		fclose(FILE);

		# Update last poster information
		if( -e "$datadir/$INFO{'thread'}.data" ) {
			fopen(FILE, "$datadir/$INFO{'thread'}.data");
			$tmpa = <FILE>;
			fclose(FILE);
			($views,$dummy) = split(/\|/, $tmpa);
			fopen(FILE, "+>$datadir/$INFO{'thread'}.data");
			print FILE qq~$views|$musername~;
			fclose(FILE);
		}
	}

	# Save updated attachments file
	fopen(FILE, ">$vardir/attachments.txt", 1) || &fatal_error("$txt{'23'} $threadid.txt");
		foreach $row(@attachments) {



			chomp $row;
			print FILE qq~$row\n~;
		}
	fclose(FILE);

	# Save updated message index
	fopen(FILE, ">$boardsdir/$currentboard.txt", 1) || &fatal_error("$txt{'23'} $currentboard.txt");
		print FILE @threads;
	fclose(FILE);

	# update board index details
	($latestnum, $dummy) = split( /\|/, $threads[0] );
	fopen(FILE, "$datadir/$latestnum.txt", 1) || &fatal_error("$txt{'23'} $latestnum.txt");
		@mess = <FILE>;
	fclose(FILE);
	($msub, $mname, $memail, $mdate, $musername, $micon, $mattach, $mip, $mmessage, $mns, $mlm, $mlmb) = split( /\|/, $mess[$#mess]);
	my( $threadcount, $messagecount, $lastposttime, $lastposter ) = &BoardCountGet($currentboard);
	$messagecount = $messagecount - $mkill;
	if( $topickill == 1) {
		--$threadcount;
		--$messagecount;
	}
	&BoardCountSet( $currentboard, $threadcount, $messagecount, $mdate, $musername );
	&redirectexit;
}