Losing Database Sessions

[eluser]AgentPhoenix[/eluser]
I'm having a heck of a time with the most random bug in my app. I'm storing sessions in the database and checking to see if the user id exists in the session userdata. It works like a charm 90% of the time, but every so often, for no particular reason, the session fails and I get logged out (at least I know that part of my app works). I checked the error logs and it doesn't show anything. The database table is fine (doesn't need to be repaired or anything), so I'm at a loss.

I'm running my app locally through XAMPP and was wondering if anyone had ever had similar issues like this. Any help or even being pointed in the right direction would be fantastic!