The only thing else I can think of is to open up uc_roles.module and goto line 256. You should see:
<?php
...
return array(variable_get('uc_roles_default_expiration_header',
uc_get_message('uc_roles_user_expiration_header')) => $items);
...
?> If that's the exact line you see, then you must be receiving a similar error on a different line because there's no way you can be receiving that same strtr() warning if the function call doesn't exist on that line.
Joined: 08/07/2007