Does the script time out, or does the browser time out waiting for a response from the web server? If the latter, then your script needs to turn off buffering, and arrange to emit some form of periodic "I'm still alive" message to the browser while you're parsing log files. One non-obtrusive way of doing this is to periodically print an HTML comment. This can double as debug info, allowing you to see trace info from your script by viewing source.

Try this: as you begin parsing each new log, do   print "<!-- $logfilename -->\n"; This will help keep the browser from timing out on you.