I get that error from time to time. I usually notice it when i leave my internet connection enabled, as well as my firewall and antivirius, or when im screwing around with the config
T-72.
Perhaps killing any and all other backapps will help you, disable any services that you dont need, like messenger, ATI help, etc...
Also make sure your not pushing the cpu to hard, this game dislikes hot cpu's apparently. lower the FSB if your overclocking.
And somewhere else ive read that If your using ATI, to set visual settings to "quality" rather than "performance". Ive not had any problems using either though.