extrended partitions are not mountable. Primary partitions can be hda1 hda2 hda3 or hda4, and the highest one in use may be the extended partition, which contains logical drives, which start from hda5 and increase. hda2 is either a primary partition, OR and extended partition, which is by definition, not mountable anyway.
what error do you get from the command?
what does "fdisk -l" say?