Support Forum

I was installing plugins on a new forum installation, and honestly, I was just uploading one right after the other.  I don't even remember which one it was, but all of a sudden, after the upload, I got the spinning boxes and no confirmation on successful installation.  After a minute or so, it was still spinning, so I hit refresh.  That was a bad idea, because then the forum is just a white screen, and every link under the forum admin shows a white screen.  I think I was uploading the post-preview plugin when it happend.  Any idea how I can fix this and try again?