4.84 Campaign bug- Mactan Base

[Dark_Daemon]

I've already beaten vanilla campaign- it was fun, but I want to try campaign with discovery (4.84, as the title says).
Anyway, I'll try re-installing, see if that helps. Thanks for letting me know it's not a permanent problem.
As for the problem itself, yeah- the entire base is missing. Just empty space, but the base still appears on the dock list, I'm able to select it, and can hit F3 to try to dock. The AI says I'm cleared to dock at dock 1 or whatever, but I just sort of loop in space instead of docking. Same thing happens to NPC's. That's actually happened with another base since I last posted, which makes me pretty sure it's a bad install.

Thanks for the advice and support, I'll let you know if the re-install works. I really hope my disk isn't corrupted.

Update:
YAY! It lives! Re-install worked. Thanks, everyone. I'm back to enjoying Freelancer- with bases.

However, I'm still curious as to what caused this wonkiness. I'm running Vista, and was switching between 4.84(for SP) and 4.85(multi). Could that cause problems?