Joj!

You're trying to recover a partition table, not check on one partition.

Run

gpart /dev/hda

(The partition table is for the whole drive, not one partition.)

gpart's unassuming home page is here

I can't speak to your problem, but in the past it has recovered partition tables which I've accidentally fdisk /mbr ed (and then remembered I hadn't quite copied everything I needed over).