No! No, no, no, and thrice no.
The Toshiba and Compaq devices are different; the hardware is different, and the PocketPC OS is
customised to fit a
particular device; a ROM from one will
not work on the other, period. Added to that, the backup format will likely be different... and lots of other reasons I'm not going to bother to state.
It's never going to work, it'll either fail to flash or it'll kill your iPAQ totally. Sorry.
Cheers,
Ref.