IMallocSpy crashes computer after exits the first Pre/Postxxxxx methods

IMallocSpy crashes computer after exits the first Pre/Postxxxxx methods ... anyone knows a reson why ?

 I just reimplemeneted the interface and it is funny how it just throws everything upside down.
To mention : I am only interested in Prealloc and postalloc so I only implement those. Could be the cause ? (The other Pre/Post fnct's I just say decalre them but leave empty)