HPL pipes

I am using the HPL and attempting to use the pipe feature. I am piping compressed files through zcat to the HPL. It works with smaller files. With larger files it abends. My suspicion is that the zcat utility buffer overflows. The work around is to use uncompress, no piping for HPL and then compress the file. Since the files are large this adds a LOT of overhead in the form of execution time. Anyone seen this or have inputs? I am running 7.30 on Solaris 5.6. Paul Storm