en-US not supported Rated 3 out of 5 stars
Hi, I have originally downloaded TB in its Dutch version and then en-US is not available in the list of languages. Don't know if that's a general problem. To solve it, you'll need to go basic: Tools > Options > Advanced > Config editor > set general.useragent.locale to en-US.
By the way: the link from the kb is pointing to an old version: