G'day AllBackJack,

Please put your code and data within '<code>...</code>' tags. See "Writeup Formatting Tips" for details.

Your first line of code appears like this:

if ( ( $g = $Grouping[$i][GEXTGRP] ) != $l ) {
[download]

However, $i and GEXTGRP are rendered as links. So, if you pasted a verbatim copy of your code, it really looks like this:

if ( ( $g = $Grouping[[$i]][[GEXTGRP]] ) != $l ) {
[download]

I suspect the doubled-up, square brackets are probably the source of the problem.