@gfvalvo sorry for the delay, yesterday and today I didn't have any time. Thanks a lot for your suggestions!
Regading the tracking down of the occurrence where I de-referenced an invalid pointer, I'll start looking into it tomorrow, but I think that will take me some time, because I guess I will have to look into all the Exception Decoder output, which pointed to five or six different files.
And regarding my if - else statements, I had completely missed that, so I will simplify it right away!