Any time an admin, or the admin user themselves tries to view another mailbox they'll get:

"JavaScript error encountered in method ZaAccountListController._viewMailListenerLauncher"

The access attempt shows correctly in the logs

"2012-01-13 11:29:38,335 INFO [btpool0-134://xxx.com:7071/service/admin/soap/DelegateAuthRequest] [name=admin@xxx.com;mid=1;ip=10.2.1.134;ua=ZimbraWe bClient - FF3.0 (Linux);] security - cmd=DelegateAuth; accountId=02dd873b-1353-4812-b86d-78e28ef1ae61; accountName=user@xxx.com;"

however the error appears every time.

The only time I don't get the error is if another global administrator logs in, and views the "admin" account - this is viewable.

Can anyone suggest what to even start looking at to try and figure out these errors? I'm presuming it might be some file system permissions issue but without an error telling me what can't be read i'm kind of stuck.

-- This happens in both windows and linux, with identical error.

We are using the OS edition.

Many Thanks