UNetBootIn disabled by Netbook Remix?

[pling]

Since installing UNR on an Acer Aspire One ages ago I've never succeeded in getting a new distro to run, even live, from USB - they just jam showing the UNetBootIn author credits. The USB is otherwise fine, so I'm guessing this is something that UNR has done to GRUB or some such thing. Any suggestions? I'd really like to switch back to Crunchbang or Puppy - UNR is friendly and pretty, but annoyingly slow and the GUI is prone to locking up.

[pling]

Could this be because I created multiple partitions when I installed UNR? I've read that some devices won't boot from USB once this has been done. If so, what do I do? GParted won't let me delete any partitions..

[pling]

Ok: I tried to fix this problem using fdisk and now I get "error no such partition" followed by the"grub rescue" prompt. The machine still won't boot from USB. Suggestions?