Your par cable probably is too long, you cant make parallel cables quite as long as serial. The bits might not all arive at the same time! ;-)
Make a serial cross-over cable, and make it about half that length (or less).
The shorter it is the more reliable it should be at higher speeds.
I remember when I made a null-modem cable and connected it up to a neighbors computer. Not the next-door neighbor - one who lived a bit further away. I couldn't tell you how long the cable is, however it wraped around a number of other people fences and I could only use clock speeds of upto abou 1200bps. :lol: