I have never worked with perl before and don't quite know what I'm doeng. I need to print some blank checks, for which I formerly used VersaCheck and Win 2000. It would never run with CrossoverOffice/wine so I installed the XP left from my last laptop, which died in 2009. I put XP on a separate disk from Linux, as I have had trouble with dual booting before. I meant to keep the Linrx disc unplugged for the duration, since I have two computers, but I slipped up after XP had fouled the MBR so badly that I couldn't even reinstalll Linux, and decided on a full format. Since I forgot I had reconnected the other disk, they were both reformatted and I have been unable to reinstall on either one.
Getting back to freecheck, the .cgi program is supposed to help set up the environment. At first I couldn't get it to run uder perl or Firefox, but eventually I ran it under Ff. It stops at line 623, can't find file %pairs_hash. There are ohly 400+ lines in the source; I guess there is some intermediate step in perl. I haven't found much help on line or in a couple of books I have. I don't think I would feel this helpless in python.
I have a word processor check sht up, complete with Erid Sandeen's gnuMICR font, but only got a few single-check test runs before my HPLJ 3330 started giving me error messages. Before it was memory; this time it's "invalid access / OFFENDING COMMAND: filter / STACK: /SubFileDecode/ endstream / --nostringval--/--nostringval--/17/false". This means little to me.

If it really said line 623, then it probably is talking about some other module used by freecheck. Perl reports the actual line in the file when it gives a line number. You need to post the whole, actual error message if you want help.