COM+ Object Losing Credential Information

Have you tried giving the account the log on as a batch job privilege?

https://support.microsoft.com/en-za/kb/312497

CAUSE This problem occurs because the Log on as a batch job privilege is not set for the identity of the COM+ package. When you set a user as the COM+ identity, COM+ adds this privilege for you.

However, if the user is a domain account, and if that user does not have the Log on as a batch job privilege set in a Group Policy Object (GPO) when the Active Directory performs an update, the identity of the COM+ package is reset, and the permission is removed.

If you retype the password, COM+ will add the Log on as a batch job privilege again for the local computer.

RESOLUTION To resolve this problem, give the domain account the Log on as a batch job privilege in the Group Policy Object in the Domain Controller.

Hope this helps -- http://social.msdn.microsoft.com/Forums/en-US/csharplanguage/thread/e17c9939-4ede-41dd-b150-d02727d9fcbe/