xp to 2000 network problem

[Lee]

Set up to share using internet router.
Everything fine for a week and then can no longer connect
to the 2000 computer.
Error message relates to vmjdbc class
Cert validation spoofing error
Can still access internet from both computers and can
acess xp from the win 2000 computer.
When connecting indicates an incorrect password but
passwords have been verified
Any help would be appreciated.
Lee