Try adding a "use Carp;" and an INIT block like "INIT { $SIG{__WARN__ }=sub { carp "Caught it"; } };"

#!/usr/bin/perl

use warnings;
use Carp;
INIT {
  $SIG{__WARN__}=sub {carp "gotcha!";};
};
my $code_err = q|
my @arr;
my $i;
$arr[$i] = 0;     # line 4 within this code snippet
|;

my $code_ok = q|my $var = ""|;

eval $code_ok for (1..8);
eval $code_err;   # 9th eval, but line 14 in this script

E:\><code>
gets me
<code>E:\>perl example.pl
gotcha! at example.pl line 6
        main::__ANON__('Use of uninitialized value in array element at
+ (eval 9) line 4.\x{a}') calle
d at (eval 9) line 4
        eval '
my @arr;
my $i;
$arr[$i] = 0;     # line 4 within this code snippet

;' called at example.pl line 17

E:\>type example.pl
[download]

Now it says Gotcha! at (eval 9) line 86., referer: http://my.server/cgi-bin/mainscript.cgi?feature=a
but still don't know what :) Is there a way to print the eval argument ?