RCTP taxiway flatten

Hi there,I have the Samsoft Taipei scenery (purchased, I believe, many years ago) and have noticed that some of the taxiways exhibit the behaviour of rough ground when you taxi over them (high thrust needed, and 'dust' clouds coming from the wheels). Also some of the runway textures disappear when rolling down them.I know this is some kind of flatter/elevation problem, but don't know how to fix it. I have a flatten program, but I don't think it will do the trick. As far as I know there is no Samsoft Scenery website or forum, but would not expect to get help there anyway after all this time.Anyone with a suggestion on how I might fix it? Thanks,- daniel