Client EM Produce OS Failed Login Errors

hi all, have anyone else met with the following problem.

we've got a SQL2000SP3a on a 2 active-active node clusters of W2K3,
this cluster in using AD.

I've found that whenever I use Enterprise Manager on my local computer
to register the above instance, it will constantly produce "Failed
login for <Domain><DomainUser>" errors in the Windows Security Log of
the database server machine. There's no failed login in the SQL error
log and I can work normally with the Enterprise Manager. The OS failed
logins error are gone once I un-register the instance from my
Enterprise Manager.

Does anyone know or met with this before?