If i install the plugin without any account added to Thunderbird, i can at least view the Addon panel but as soon as i add an IMAP account, it starts blinking in the drop-down and i cannot view any e-mails at all.
TotalMessage has been tested on win and linux, but not mac. Please open the Error Console and post anything that might seem relevant.
If you have pref extensions.totalmessage.headerListEnabled set to true (restart required for change), the Sort by and Threads menuitems are disabled, as this functionality is much more easily visualized and changed using the menus and buttons in the threadpane header column. Explained in the wiki.