Tool Palettes ARX Error

I have been using my tool palettes in LDC2009 and all of the sudden started to recieve this error message when dropping a block from the palette:

ARX_ERROR: eLockChangeInProgress
ERROR: AecDbVarsDwgSetup could not update values in AutoCAD environment.
Document "Drawing1.dwg" has a command in progress.
Hit enter to cancel or [Retry]: *Cancel*

When I hit enter, Autocad closes down.

I have tried restarting autocad, and restarting my computer to no avail.

Has anyone else been running into this same problem?