I/O errors are sometimes caused by hardware problems (doesn't necessarilly mean your drive *is* bad, but it may mean it's *about* to go bad), but that's not necessarilly the only cause. Do you have any important data on your system? If so, I would make it a necessity to back it all up, just in case.
Worst case scenario, you can boot to the LiveCD, try gparted, and see if you can partition the drive with no problems. Sometimes it's only the data on the partition that's screwed, and there's nothing physically wrong with the drive at all, in which case wiping all partitions on the drive, then repartitioning the way you had it before should fix the issue. However, you should only do this as a last resort, as this will totally erase everything on your drive.
Last edited by champton; 03-19-2013 at 02:05 AM.