Navigation Problem - Walking thru walls and thru the ground

In Multiplayer mode, when I join a world I seem to enter the world ok in creative, but there is a navigation issue. I can move through walls, go through the ground. I can't actualyl "land" on the ground. While underground, the world is rendered strange. There doesn't seem to be a fix I can find. This also happened in the version before current version but I don't have a crash report.