Parameter name: project

VB project in VS2005.

Got into a condition where trying to open the project properties window generates an error: "Value cannot be null. Parameter name: project". Once I hit OK on the message box, the project properties window opens normally with no obvious errors. While this condition is in effect, the trickle down problem is that the dataset designer with existing tables and adapters cannot locate the connection string they were built with in the Application Settings. The connection string does exist with the correct name in the Settings tab of the project properties. I suspect the dataset designer is catching the same error I get when opening the project properties, and aborts the search for the connection string. I have searched everywhere and have no clue where to access/modify/fix the 'project' parameter. Anyone know