Jenny:
I'm getting the error message "C compiler cannot create executables" when trying to compile something.
Is that because you don't have part of the compiler toolchain installed (bin86 and friends)?
Don't know if anyone remembers my recent muddle with installing things from the testing in debian in a wild frenzy, ahem, but it all seems to be sort of not working. I tried installing task-c-dev, but that depends on libc-dev, so I tried installing libc6-dev. Again, unhappy, suggested unmet dependency was libc6 (= 2.1.3-19) but 2.2.4-7 is to be installed. "Broken packages" it said.
My best guess would be to try "apt-get --reinstall install libc6" to see if it resolves it, or try getting the libc6 package from stable, installing it and removing all the extra stuff that breaks. Your other option is to move /etc/apt/sources.list to using testing, then "apt-get dist-upgrade". I'm not sure which will break less stuff for you, though.
Sniff. I broke my box.
We have the technology. We can rebuild you.
Sorry all. I'll bring chocolate biscuits on Sunday, I promise.
Yuck, chocolate.