Hmm, since you didn't specify how the filesystem was created on that partition, I'm going to assume you used a version of windows to create it/format it.
If you can, back up that data to a working/usable partition or CD (if you can't, good luck...). Then, follow along:
We will change the ID of the partition to a Win95/FAT32 partition using fdisk:
Press "L" without the quotes and lowercase and hit Enter
Feel free to play around and try variations of b, c, or f
To change the label, press "t" without the quotes and then choose b,c, or f
Then, remember to write your changes (again, remember to back up your data first, even though it's not likely to lose your data, it's not safe to take a chance when messing with the partitions):
Hit "w" without the quotes, and Enter to write and quit.
After each change, try to mount the device again, using vfat, and of course, use the full mount command:
/bin/mount /dev/hdb7 -t vfat -o umask=000 /mnt/win_e