i cant really say much about the bug, it basically just segfaults when i go to [tools/mail settings] this is evolution 1.0.2. i tried doing 'emerge --unmerge net-mail/evolution' but it says the package doesn't seem to be installed which is another bug.
You need the --all flag for --unmerge to find the only installed version. As for the fix, see bug #10 *** This bug has been marked as a duplicate of 10 ***