During install I choose to mount my only vfat partition as /mnt/dosc. The installer allowed me to do this. However, after formatting the filesystems and it started to try and mount everything. The /mnt/dosc entry caused the installer to throw an exception and completely shutdown. I had to repeat the whole installation procedure. Unfortunately, I cannot find the floppy that I wrote the error out to, but I believe you should be able to recreate this fairly easily.
Should be exactly the same bug as Bug #18032, please take a look at the backtrace there. *** This bug has been marked as a duplicate of 18032 ***