You have to assure within Blender that the mesh's and the armature's origin are both placed at the zero of the world coordinates, their scale and rotation have to be set to 1 and to 0. (Look at: Object --> Clear/Apply --> Apply Scale/Rotation... )

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