Based on Google search http://www.google.com/search?q=agcutils.dll agcutils.dll which appears to be a file from a product called Webshots Desktop and Toolbar.
Go to the following website and read the Comments for more information. New Webshots Desktop and Toolbar! http://blog.webshots.com/?p=1017 or http://www.webshots.com/ My Guess is that you uninstall Webshots IE Toolbar and see if that solves the problem.

Is it only when you use the hotkey? What if you right click > Auto-tag from web? Did you ever install an add-on to auto-tag from a different source?

when I use "Ctrl 'L'" to find an album cover from the internet, I get the following error message:

access violation at address 0d7b579d in module 'agcutils.dll'. read of address 00000000.

Any ideas as to what I can do to fix this?

Thanks,
Aodh