winipac - runtime error 6 - losing programming

[big daddy]

Had my arcade for 1 1/2 years or so and it's been working fine up until now.

Lately I seem to be losing my programming on my IPAC fairly regularly (i.e I have it set to program button 1 for B, 2 for c, etc.  Yet sometimes something happens and my button 1 defaults back to cntrl and button 2 back to alt, etc.  If I open the Winipac programming utility and hit the program button again, it says "download complete" and then works fine for awhile then eventually happens again.

Well my kids usually play it so I was never sure what exactly was happening, but today it was working fine then when I was starting up galaga I got the following message
Title: WinIpac
Message: Run-time error '6'.  Overflow.

Right after this I lost my programming and then had to go into the programming utility to get it back again.

Any ideas?  Should I re-install the driver?  Is something hardware related? 

Also I'm running XP and using mamewah as my front-end, in case it matters.