files attached from folders mounted as \\<computername>\<sharename>\filename fail on sending. Error message is: "Sending of Message Failed. Please verify that your Mail/News account settings are correct and try again." Mapping that path to a drive letter makes sending the attachment work. I am fairly certain that this is new to 0.9.4, as I've not seen it before, and I'm fairly certain I've done this many times.
This should be a dupe of bug 55591. Please reopen if you disagree ! *** This bug has been marked as a duplicate of 55591 ***