Thanks again for your advice and help - we all have to start somewhere to gain experience.

"Hello World" @ 1mb - oh! Would never have guessed!
Debugging - I do/did understand. What I didn't know how to do was your suggested $Debug plan. I will of course be using it - as well as reading the CGI Help Guide.
If you don't want to see my code, skip this bit ;-)

my $list;
foreach $a(0..$#my_array){
    $list .= qq¿<TR>\n¿;
    foreach $b(0,1,8,16,14){
        if($b == 0){
            $list .= qq¿\t<TD >${'flag_'.$languages[$my_array[$a][20]]
+[1]} ¿;
            $list .= &build_link("?act=subscriptions_view&what=$my_arr
+ay[$a][0]&m0=$m0&m1=1",$target,$my_array[$a][0]);
                $list .= qq¿\t</TD>¿;
            }
            elsif($b == 1){
[Note: $email is null: Included - script fails.  Excluded - script com
+pletes. ?!? DEBUG should find out why.]
                $list .= qq¿\t<TD >$email $my_array[$a][2] $my_array[$
+a][1] </TD>¿;
            }
            elsif($b == 14){
                $list .= qq¿\t<TD ALIGN="right" >$cat[$my_array[$a][14
+]][0]</TD>¿;
            }
            elsif($b == 16){
                $list .= qq¿\t<TD ALIGN="right" >$diff[$my_array[$a][1
+6]][0]</TD>¿;
            }
            else{
                $list .= qq¿\t<TD ALIGN="right" >$my_array[$a][$b]</TD
+>¿;
            }
        }
        $list .= qq¿</TR>\n¿;
    }
    $list .= qq¿</TABLE>\n $files_found <P> \$email = $email ¿;
return $list;
[download]

I'm sure the above code is fairly rudementary and undoubtely 100's of ways exist to achieve the same result, but this is what I've got! I have already spent more than several fruitless hours searching and trying to find out why and what 'breaks' just by including an empty variable '$email' in the above code. Again, DEBUG might hold the answer.

I will of course be following up on all your suggestions.

Thanks again for your time and help.

R.