sometimes I get session write failure

I've searched this mailing list and couldn't find anybody with a similar problem. I am seeing periodic session write failures on my server. I get the classic PHP Warning: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/home/t-shirtking.com/session_data) in Unknown on line 0 Of course I checked the permissions. Everything is fine there. Garbage collection runs well. The directory doesn't get real big. The thing I couldn't find on this mailing list is that sessions work. I can't duplicate the message. So I only sometimes get the error. I added the session write close command in an include file that gets appended to every page. Why in the world would I only sometimes get this error? Thanks, Josh Bauguss josh@zebotech.com