What system do you have? Mac probably?
There are 2 options. The first is to tweak variables: vm_game, vm_cgame, and vm_ui.
Set them to 1 at first, if it does not work - to 2 and finally to 0. There are only 27 possibilities, of different settings , but as far as I know setting them all to 1 solves the problem in most cases.
The second option may be interesting if you don't use punkbuster. Get ioq3 (binaries, or source if you can compile it) at http://ioquake3.org/get-it/ , install and use it instead of 1.32c pointrelease. ioq3 contains much less bugs, but doesn't support punkbuster, which is proprietary stuff.
Drop a line if you solve the problem, especially 'bout the variables case, because i'm not sure which combination works.
Cheers