If I recall correctly, my Mac G4 laptop won't power the CFV either, I must use the CFV battery to shoot to this laptop. There are Firewire adapters that plug into the external slot that provides A/C power for peripheral Firewire devices.
" Body: SWC , Exposure Time: <1/8sec." - Jurgen.
Jurgen, did you try just extending the Exposure time to 1/2 second? I was experimenting with the CFV for a job this past Sunday, and was using the ground glass and a "Chimney" finder. I was getting the smeared magenta frames, but when I lengthened the back's exposure time via the menu, it was fine after that, I left the camera selection on SWC and no sync cord was necessary. Pictures came out fine.
"I had my first area come up on my CFV back today, saying something like internal error, which I hope was due to the battery getting low."
Yes a weak battery can cause issues, but it's not necessarily the only cause. Definitely get a second battery to swap out if this happens to eliminate that as a possible cause.
Any inadvertent user error will result in a "Error Code". OR, if the back gets confused (it is a computer), it'll error out, ( "Reboot" has also now become a photographic term : -) Usually, powering down and then removing the battery will clear the problem. If it doesn't, then the next step is to remove the back and reinstall it.
If you suspect that it is an error on your part and you can't remember what you may have done to cause the problem, go into the menu and reset "Factory Defaults" which will eliminate any setting you may have inadvertently set.
Not that these steps are a cure-all, just the ones to take to quickly eliminate issues yourself. Beyond that seek council from Hasselblad tech support.