Marcin and all,
As far as i know, a ruptured disc can never really heal . If the inner disc stuff is spilled outside, than the disc is open and will be like that till the day i quit this place. The disc simply doesn't close.
I see a few guys in my regional club doing jumps having the same problem. Thanks god, in the past two months the pain is seriously lower than it was and i am jumping once a week. I recommend doing swimming, stretching and walking. Still, the only thing that i am afraid of in skydiving is the canopy opening process. Do you know what the opening process does with the spine? Is the spine being stretched or compressed in the opening process??? If compressed (bad!) than what do you suggest to do in the process in order to get off as much pressure as I can from the lower back?