Forum:I Can´t enter The Pitt anymore

I have the PC Version of Fallout 3, and all the add-ons (including Point Lookout) installed. The problem i have is since i completed Point Lookout (and return to the Wasteland) every time i try to fast travel to The Pitt, my character appears swimming under water and i cant reach the surface. I also try to reach the tunnel that leads to the Pitt by foot and it never appears! It's like it was never there (the place that usually contains the road its invisible, only the trees appears floating in the air, marking an invisible road). All the armor, weapons and achievements unlocked remains untouched, but it's very strange. Is there any solution for this? Has anybody else suffered this bug?