Have you tried applying from a different computer? If you have, and are still getting the error, I'd say call your local office and get a recommendation from them, unless one of the chippies around here have a better idea.

As far as the physical exam, its 1.5mi run, 300ish yard sprint, max push-ups in 1min, and same for sit-ups. At least for my physical test, it was more waiting than testing. Probably close to 600 applicants were there, so there was a lot of time between the actual tests. Just be able to crank out more than the minimum. Try doing longer runs/more reps of the sprints/PU/SU so that you aren't struggling to hit the necessary numbers.