Re: [290.10] Systemfreeze NVRM xid:31 (Ubuntu 11.10 Kernel 3.0.0-13)
Although still using driver version 290.10 I was able to nearly get rid of those system freezes. In my case, this problem occured quite often when I was using flash (e.g. youtube).
I tried different flash player versions but that didn't solve the problem.
Eventually I use a firefox plugin (Flash video replacer) for replacing the flash videos with their corresponding WebM version, which works fine for me (as a temporary workaround).
May Flash also be a possible source of problem on your side?