TB 78.4.1 Fresh Install - Cannot Add Email Accounts or open Options

I have been using TB Portable for several years, successfully. Recently, with the update to v78 and up, my TB Portable installs have started to fail (on several different systems). I still have a backup version of v68 and it seems to still be working.

Currently, I have tried reinstalling multiple times with no success. Most recently, I have reformatted an internal drive and have installed only the PortableApps(17.1.1) Launcher and TBPortable(78.4.1) running on Win10Pro(v 2004). The app will launch. I see the main screen, but I cannot add any new email accounts. I can add an Outgoing Server via Account Settings, but clicking the "Email" button on the Start page throws an error & does nothing. In the Error console it throws all sorts of errors - lots of "NS_ERROR_FILE_UNRECONIZED_PATH" errors.

Also, I cannot open the Options pane. Again, throwing an error - "No such tab mode: prefrencesTab"

So, given that this is a fresh install and it is still failing to work properly, anyone have thoughts about a cause?