I don't know if it helps, but when you compile the application the memory location that points to the crash changes from 0x00000000 to 0x00133000. It indeed seems like some kind of a bug in VB6 at the moment, but why it happens is harder to tell.

Oh and Milk, my error was that I didn't make sure the variable type was correct. I should have done like this:
AppendBytes bytTest, CSng(10.1), CBool(False), StrConv("Test!", vbFromUnicode)

Which then gives š™!A Test!


I also updated the shorter version of AppendBytes to be even shorter.