wp-cache seems to be causing problems with commenting

Hello all-

I recently had to implement wp-cache because my Web host warned me that I was eating up a lot of their resources. It solved that problem ably but seems to have caused another.

My users (and I!) are having intermittent problems posting comments to the site. Sometimes when posting a comment, after pressing the appropriate button to upload the comment to the site, instead of being returned to the individual post screen the user is just taken to a blank screen, and the comment never appears on the site.

I’m currently using the filosofo comment preview plugin but disabling it causes the same results. Sometimes you can go for hours and not have any problems, and then sometimes any attempt to comment results in this problem.

I believe that this problem is related to wp-cache because I never had it before I implemented caching. However, I’m not sure exactly what might be causing it. None of the comments-related pages appear to be listed in the “cached pages” lists. Help!