Windows: QML Debugging does not work: Freshly built qmlobserver/qmldump crash

Situation: The Qt version used for the project is MSVC2010-built debug. Qt Creator is taken from the package (VS2008).
No usable stack trace occurs.
Same with MinGW.
Also, after this happened, the debugging session is still active and causes an exit prompt (that is,. the case of a crashing observer is not properly handled in the engine).