Rollup Update install error - error code 2771

When trying to install the rollup update 7 on a hub/cas server, I get the following error almost immediately:
"The installer has encountered an unexpected error installing this package,.  This may indicate a problem with this package.  The error code is 2771."
I get the same thing when installing from a downloaded install (that I've used on other servers) or via windows update.

I also get two errors in the event log:
1. MSIinstaller - event id 10005 - same as above but adds "The arguments are: AdminTools" at the end.
2. MSIinstaller - event id 1023 - "... could not be installed.   Error code 1603.  Additional info is available..."  (no add'l info is in the log file referenced)

I had a similar, if not exact, problem trying to install rollup update 6 and couldn't find any info then...  or now.   Saw one post about disabling symantec endpoint protection (which we don't use) but I tried closing our trend a/v but no diff.

Oh yeah, the server is Win2k3 R2 x64 SP2.

Any help would be appreciated.
Thanks
Frank