Thanks Pavel V. and Robert R. for your helpful suggestions. I've made the changes to the code you both told me about. Finally used vc71 to test compiler errors. I also implemented dummy serialization functions for date_time components for now, just to get the whole thing to compile. So, I can compile with vc71, but couldn't do so with BCB. So, just out of curiosity, I tried compiling with BCB's command line compiler and got some more errors, which I then fixed; and now I CAN compile with BCB's CLC but still can't from within the Builder IDE. I can only conclude that it's a project specific option that's causing me trouble. BTW, the docs (both the 1.32.0 distribution and online) have a typo in the "state_saver" section: <quote> History This is a generalization if Daryle Walker's io_state_saver library. </quote> I believe it should say "of" instead of "if". Pablo Aguilar