On Lion 10.7.3, when trying to empty the Trash from the GUI the items to be deleted are counted, and the the dialog doesn't progress anymore:

Stopping emptying the Trash doesn't help much either: the only thing changing is the status on the dialog that now reads Stopping...
It's reported that resetting the PRAM does the trick, and I know that I can just force the removal from the CLI, but can somebody help me understand why this is happening and how to fix it?
