for my $logFile ( glob("$logDir/${logPrefix}*") )
{
open($log, "<", $logFile) or die "Can't open $logFile for reading.";
open(FP_OUT,">total_transactions") or die "cannot create file total_tr
+ansactions for writing";
}
[download]

This bit looks weird. How many log files do you think you'll be processing? You're opening multiple files on the same filehandle. Only the last one opened will be processed.

And the standard suggestions about adding strict and warnings apply.