After I enter an e-mail address and subject, I hit send, which immediately returns "Unable to Export: An Internal Error has occurred: AgExportRendition: can not import a photo exported to a temporary location."
I found a report of this bug for the Beta, and tried the solution there of deleting the "For Email" preference file. Did this and restarted LR, but it made no difference.
I am running with Administrator privileges on Vista 64bit, using MS Outlook 2003. I upgraded from LR 3.6 to LR 4, and am in a catalog that was converted from LR 3.6 to LR 4. LR 3.6 and a 2.x version are still installed on the same computer.