What is "Locum" in root user, and why is it 101% of processor usage?

Locum is a helper tool that runs with escalated privileges in order to do things the Finder cannot. Sounds like it's stuck. Have you tried rebooting?

orangekay wrote:
Locum is a helper tool that runs with escalated privileges in order to do things the Finder cannot. Sounds like it's stuck. Have you tried rebooting?

FYI: The OP said he tried rebooting which temporarily fixed it but then the problem returned.

So he did.

Any AFP dropouts or anything like that?

Do a Google search for 'locum for os x' without quotes. There will be several listings related to this that provide explanations about locum and what it does (and why.) These may help provide some answers for you.

hdansmith wrote:
My Intel Core Duo MBP has been sickly lately; running VERY hot all the time and just not so great. I looked at the activity monitor last night and found the FINDER was using 185% of my processor capacity. I rebooted and that seems to have quieted that down, but this morning I see that "Locum" the root user is using 101% of my processor capacity . . . and the temperature is going up.

What is Locum, why is so demanding, and is there a fix?

"The Finder application links with a private Apple framework named DesktopServicesPriv.framework, which helps with taking out the trash. Bundled as a resource in the framework is a setuid root binary named Locum, which the Finder uses to delete files that it normally wouldn't have access to delete...."

http://unixjunkie.blogspot.com/2006/10/finders-locum.html

I am not sure Locum only works with Trash, but the point is that Locum does things Finder cannot do, most likely because of privileges.
Check the activity monitor and console logs for information.