[eluser]rip_pit[/eluser]
Never tried under linux at home but i hosted a CI projet with TA auth on a linux server (unix ?) and all went fine.
Did you look in your apache error logs ? and php error logs ? sure you'll find some info there.
Let us know if you find something. Maybe your apache or PHP needs mods or settings enabled manually under linux.
can you clarify when does your TA not working ? when you press "login" ? what happens ?