I've got an old Keil compiler V5.02 with hardware dongle that I'm trying to get to work with the Cygnal F005 Dev kit IDE on Win XP.
you are trying to make something XP compatible work with something that is not.
you have several options
a) as Andy suggest compile and link on the old machine and network it over.
b) to the best of my recollection the older Keils work on XP in commandline mode

but

if you are an IDE fanatic and insist on both (something XP compatible (SILabs debugger) and something that is not (ancient Keil)) to integrate you are out of luck.

The SILabs debugger (ignore the other functions of the IDE) will, agsin - to the best of ny recollection - work fine with files from an older Keil.

I work (with a new Keil) happily in commandline Keil and SILabs debugger.

Erik