Noone seems to have made the obvious suggestion: go to a teacher who specialises in jazz and get them to recommend a good starting point. I don't think trying to play bebop is the best starting point as far as walking lines go.
When I finally met the right teacher (after two years self-taught jazz bass) he basically took me back to the start and got me playing very simple walking lines over blues progressions and other simple forms, of course I wanted to play very complex material straight away but having those basic principles down pat is the key to expanding beyond them imo.
Recommended listening: Walter Page with Count Basie, Paul Chambers and Ron Carter with Miles Davis, Ray Brown with Oscar Peterson of course, as much jazz as you can get hold of. There's so much you can learn from everything that's ever been recorded, but start with something simple!