taxiway shimmering in ACOF & other things

[tshikwara]

I dont know if anyone else has this problem, but my home airport YBHI (Broken HIll in Australia) has shimmering taxyways. They disappear completely from view just as you get to it, leaving it appearing as though you are on grass. I have changed the default landclass to make the surrounding area dirt. The default scenery had a 5 storey building on short final!! I changed the scenery to desert scrub and it looks better, but the taxiways disappear as mentioned. Also, the aircraft crashes into invisible objects on the taxiway, and resets the flight. Any thoughts on this
TA