I remember this prob with some surfaces but forgotten the work a round (maybe rebuilt after checking texture again)so maybe this was anactual bug from back then and an upgrade to 6.6 might sort it out because I know it dissapeared after I upgraded (e.g. solid content produced water effect only when a 'water' textured was applied).
But as you say, give your character a terrain to walk on as that is what you were suppossed to have done I think.
PS. Good to see you back
