From the sounds of it, it's likely that you've either cracked the gas tube or cracked a solder joint. If you're not familiar with soldering, it could be complicated to fix yourself. On the other hand, if you are familiar, it sounds fairly easy to fix.
Your best bet? Either use this lamp as a sacrificial lamp and learn how to solder, or find someone who knows what they're doing. I do my own repairs, and it's not hard to learn. You just risk ruining a lamp, but hey, it alread doesn't work. What have you got lose?!?
I'm spiralling down to the hole in the ground where I hide - R. Waters