What minimum version of the OS does that version of MCE require? Win 3.1 is pretty old and MCE may not install under it.
Is your card an HP card? Other brands may not work. Also is it SRAM or Flash. If SRAM then it will almost certainly have a door on it access a button battery, Flash card won't have a door. Flash PCMCIA cards will NOT work in any equipment that's intended to use SRAM. My experience with a bunch of leCroy scopes, an old HP SA and some NV gear and they all required SRAM cards and Flash would NOT work in any of them.
Does your HP 8935 have an option setting to save files in an ASCII, text or other computer readable form instead of the HP tokenized file format?