"A runtime error has occurred. Line 49: top.folders.location is NULL or not an object."
Compose a new email or draft a reply to an existing one. Press the SEND button. Each time I've gotten this message, it's was preceeded by a longer than usual wait after clicking the button. It's not 100% reproducible but I've gotten it several times already.
!!! NOTE !!!
The email still reaches the SMTP server and gets delivered normally.