This is an old bug that has come back again. The shortcut to load the system mailer launches evolution in the mode it was last in. i.e. it just loaded the calendar instead of the mailer
This is due to # Remove arguments GCONF="`echo $GCONF | cut -f1 -d" "`" Which does the wrong thing for evolution. Removing that line fixes the evolution problem, but makes thunderbird come up with a composer window instead of the main window. A clean solution would require to store two separate commands, one to bring up the mail client, and one to compose a message.
htmlview-3.0.0-15.fc6 has been pushed for fc6, which should resolve this issue. If these problems are still present in this version, then please make note of it in this bug report.
Closing this per the previous comments from Fedora Updates System. Please feel free to re-open this bug if you encounter the problem again.