First mission bug (NEED HELP)

[pagem4]

On the first mission, as soon as the cutscene ends, instead of spawning one the beach I spawn out inthe water, with no path to my squad, invisible walls in random places. I looked at a walkthrough and they were in a different place! What do i do?

EDIT: It was fixed after a full reinstall of the game. Should have updated this post sooner.

[Capt Marvelous]

Not sure... might be a glitch? Have you follow exactly through the walkthrough? Try to verify your game cache.