Something you are running on boot or from WBStartup is breaking your memlists, probably by trying to free RAM twice or RAM it didn't allocate. In short, some prog is buggy, and it's wreaking havoc on your ram.
You can either disable all your add-ons and patches and re-enable them one at a time, or you can run Enforcer early in Startup-Sequence, which will display a hit with the name of the offending program. It's not a beginner's tool though.
