I did try this and it worked temporarily. The permanent cure, (In Vista)
was to go to Start: on the Right Side, under Control Panel, there is choice
for DEFAULT PROGRAMS. Click it, and then Click ASSOCIATE A FILE TYPE OR
PROTOCOL WITH A SPECIFIC PROGRAM. Scroll down all the way practically to the
bottom. Highlight the MAILTO (MailTo Protocol). Then near the upper right it
says "Change Program". Once you click that, the choices for the Mail To
should come up. This worked for emailing. I am not 100% sure, though, if
this is the absolute answer to your problem, but I do hope that it helps.