This is a known issue. There are some problem with Disk Utility under 10.5. First, it has not been updated to handle the new indexing methodology used by Spotlight, which is why it takes forever. Second, I
believe the problem with ARDagent.app is a result of the latest update for the Apple Remote Desktop client.
If it really bothers you, you could probably attempt to correct it yourself. I believe the problem is that the update altered the permissions for Apple Remote Desktop client, and I suspect that this client is what's used in the new iChat for screen sharing, among other features (which is why it exists at all in a default installation). Deleting it entirely would not be advisable.
That is, SUID is the command for Set User ID. You could getuid to see what the user ID is for the ARDagent. You could change it yourself with setuid. I wouldn't bother.
ACL stands for Access Control List (I believe), which if I understand it right is a permissions setting for a folder, file, or directory.
If I'm understanding the error right, the user ID for the ARDagent has been changed, most probably the update. Disk Utility does not know and/or understand how to correct them (or if they even need to be corrected, which I suspect they might not need be). Perhaps to allow superuser/root access via ARD, I don't know. The two most common extensions to the error are ACL expectations on "Applications" and "Library". My guess is access to these folders is being modified to be either allowed or denied by the ARDagent.
There are some clues in the release notes for the update that lead me to believe this:
1. Support for Mac OS X 10.5 Leopard's Remote Management settings in Create Client Installer and Change Client Settings task
2. Support for Mac OS X 10.5 Leopard's Remote Management settings in kickstart
3. Open Application task now launches applications on Intel based clients
The last one may pertain to ACL changes on the "Applications" folder.
It's likely that this isn't actually a "problem" at all, but rather the way things are supposed to be. I'm assuming that Disk Utility actually has an exceptions list for things like this, as Apple employs many non-standard/UNIX features. I suspect the "fix" for this will simply be adding these messages to the exceptions list for Disk Utility.
