Verified that another cartridge works in that N64 to make sure system isn't broken? Verified if problem could be related to power source or video input/output, etc.? Otherwise, I am sorry, that sucks. If it's just the cartridge, I'd try and get another copy, though I hear they're spendy. Good luck.
Damn that sucks man. Hopefully you can find a copy of the game that's working and at a decent price. I feel incredibly lucky that I bought the game brand new at the tail end of 2001. I think I got it for $15. The gamecube had just come out then so stores were selling N64 games for next to nothing. I'm pretty sure I ordered it off of Amazon. It's actually the last N64 game I purchased, pretty sure the box and the manual are lying around somewhere at my parents house too.
PSN: spacedirtyjerz Black Ops 2 might have the worst online experience of any game I've ever played