You're almost certainly running into structure padding differences. Even when you define the padding as closely as possible given compiler directives, platform/compiler incompatibilities will still creep in.
For starters, I see a "Boolean" in your definition above. That can range from one to four bytes. I also see some char[] fields that are not long word multiples, which is another likely place for a trying to be helpful compiler to insert some pad bytes for you behind your back.
Having debugged more of this kind of thing in my game-porting life than I really care to think about, you might as well just print out a long list of printf(sizeof(StructureXXX)) statements at the beginning of the file code reading, and see where the differences show up on each platform. Trying to analyze where the differences will be from reading source code, although you can often make some good guesses (any compiler-defined type like "Boolean" is a big waving red flag, for starters), can very well actually be completely impossible.
