Hi there! It's probably updated or something, just go to www.physicsengine.com (and try again ) This physicsengine plug-in for 3dgs, especially for users with say A6 commercial (orA5 versions) and below. You will get quite some options; rag-doll physics, car physics etc. (just check it out ok?!)
the version without examples is still online. the big download caused too much traffic. once there are new example levels which waste less space it will go online again!