Maybe, playing around with the d3d lod-factor helps:
http://www.conitec.net/beta/ad3d_lodfactor.htm
Or, look in your 'view.clip_far'.

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt