What exactly do you mean by "crashes and stops answering"? Do you see an error message?

Have you tried running the script under the Perl debugger (see perldebug)? Try interupting it when the problem occurs to see what it's doing.

Are the values for minRow, maxRow, minCol and maxCol correct? It looks to me like enough rows with bad or missing maxCol values could cause a significant pause in output.

How much memory is the script using? You can get a rough idea by watching 'top' in a separate window while the script runs.

-sam