I had this problem with wp-cache and was advised to use wp-super-cache instead, but the problem persists.
As soon as I log in to my blog (the admin panel), the site refuses to load. Not just on the computer I'm logged into, but any computer!
When I clear the cache and cookies, it seems to start loading okay once more.
This is driving me nuts. I don't seem to be able to find any caching solution that doesn't kill the site in some way.
Back to un-cached for now :(