Mine

<!ENTITY removedupes_dialog.action_label                "Action:">
<!ENTITY action.move.label                              "Move to:">
<!ENTITY action.move.accesskey                          "m">

Failed erasing messages.
Failed deleting messages.
Failed moving messages to:
Can't move messages to folder

Oh, also, I'd like the names of the special folders:

Inbox, Trash, Sent, Drafts, Unsent, etc.