I noticed two errors in your code. First was the quotes that Fastolfe pointed out above. The second was that you said you wanted to split on the third element of the array ($array[2]), but in your code you actually used "$split[1]".

I used the following snippet of your code (with the proper array index) combined with the foreach loops I added to print out the values stored in your arrays for debugging. This is a technique I use regularly to find out if the arrays (or hashes) I use actually contain the values that I expect to be held.

$html_this_file = "5|8|2#3#4#5|5";

my @split = split(/\|/, "$html_this_file");
my @prefs = split(/\#/, $split[2]);

$count = 0;
foreach  (@split) {
    print "\$split[".$count++."] = $_\n";
}

$count = 0;
foreach  (@prefs) {
    print "prefs ".$count++." = $_\n";
}
[download]

HTH...
ryddler