If you are using Virtual Machine Manager 2008 beta and the refresh library job is failing with the following error

Error (2912)
An internal error has occurred trying to contact an agent on the <SERVERNAME> server.
 (The inherited access control list (ACL) or access control entry (ACE) could not be built (0x8007053C))

then you need to remove the VMMServer group + SYSTEM permissions from both the share permissions and the file permissions for this library server's shares (so there are 4 entries to remove total). This is a temporarry workaround for beta and in RTM this issue will no longer exist.

The library refresher will ensure that the permissions on the share are correct each time it runs, so once you remove the permissions and refresh the share they will be back and everything will run normally.