Weird results

Shooting a LightPhase tethered using C1 on a Sony laptop with XP SP2 and an Adaptec FireConnect AFW-1430 IEEE 1394 PC Card I sometimes get results as shown below. It was usually only once or twice within every 50 shots or so, but yesterday it started to happen with almost every shot taken. I shut everything down, disconnected the card, reinstalled it and started back up and evrything went pretty much back to normal.

Can anyone tell me what is causing this and how to prevent it?

http://kordaystudio.com/Weird.jpg