[BirdOPrey5]

You could override the forums setting in options be editing two plugins...

In plugin Manager edit these two plugins:
Enable Anonymous Posting (Posts)
Enable Anonymous Posting (Threads)

Change this line in each from:

	$anonyforums = explode(',',$vbulletin->options['zointsanony_forums']);

to:

	$anonyforums = array(2, 3 4, 5);

where 2, 3, 4, 5 are the forumids of the forums you want to enable anonymous posting in, use as many or as few as you want.

I don't know why the forums wouldn't stay selected though, may be the sign of a bigger problem. Does being enabled Yes/No stick to Yes at least? If not this won't help.