Palm m100 hotsync problem

I have both Win XP and Win 98 in my PC. I have Palm desktop software in both OS. I have been doing hotsync for years without difficulty. Suddenly it has become impossible in both OS.
In Win XP; the process goes upto "synchronising Datebook" and then this goes on without end and after an hour I have to close the program.

In Win 98, it goes on upto "synchronising datebook" and then message pops up saying that the program has performed an illegal operation - hence closes. The 'details' says " Hotsync caused an invalid page fault in module DAT CN 20.DLL etc". The Log says" The connection between yr handheld and desktop was lost. Some of yr data was NOT backed up"

I have tried soft reset. I have re-installed desktop software from the CD. But nothing helps. Pl help.