It seems strange that someone else was getting that error on the same line, but I don't understand why a missing phrase would be the problem.
I have the code for version 4.2.0PL2, and I have this code at line 4008:
Code:
if (!function_exists('fetch_phrase') AND !VB_API)
{
require_once(DIR . '/includes/functions_misc.php');
}
It seems to me that the only way that could not load is if your script was defining VB_API as something other than 'true' (or if fetch_phrase was already loaded, of course).
In any case, if it were me, I'd put in some debug statements. For example, I'd probably put a die() right before the require_once and see if it's getting there at all. Or maybe comment out the 'if' line and the closing } and so it's always included, and see if that fixes it. (Of course those changes are just temporary, you'd remove them after you see what happens).