Is it possible to do a url check?

[ZiNgA BuRgA]

Try replacing your instances of $fid with ($fid ?: (THIS_SCRIPT=='forumdisplay.php' ? (int)$mybb->input['fid'] : 0))

Not tested, so IDK if it works.

(11-16-2014 06:19 PM)Sama34 Wrote:  IIRC in the header you will need to use {$mybb->input['fid']}, probably <?=($mybb->get_input('fid', 1))?> in 1.8 for security reasons, no sure if really necessary.

Unfortunately doesn't work for non-forumdisplay pages... :/
forumdisplay is actually special in that $fid isn't set in global.php