Ted,
Have you tried changing the FTP client parameters and accessing the Compaq site? Maybe there is something strange in the exchange.
Try logging (to a syslog server) at the debug level and access that site. That will give you a better idea where the PIX sees this breaking down. (Note: you may want to to do this after hours depending on the traffic at your firewall. Debug will generate many syslog messages.)
If that doesn't work you'll either need to do FTP transfers for that site outside the firewall or disable the FTP fixup. I'd suggest doing the transfers outside the firewall.
Liberty for All,
Brian
Brian Ford | brford@cisco.com | brford@yahoo.com | 51 75 61 6c 69 74 79 20 6d 65 61 6e 73 20 64 6f 69 6e 67 20 69 74 20 72 69 67 68 74 20 77 68 65 6e 20 6e 6f 20 6f 6e 65 20 69 73 20 6c 6f 6f 6b 69 6e 67 2e | Email me when you figure this out.