I've had the same problem with a cuple of bows I made and from my experince I can tell you that black locust is a good bow wood, but it does not forgive any tillering mistakes you make. Another problem I found with it is that a too high humidity content of the wood makes it even more susceptible to compression cracks. A light heat treating worked well for me, making the wood a little more compression resistant. Unfortunatly I don't think that your bow is salvageable, those are a lot of frets... I'd suggest you to start again with a wider stave, season it very well, take off the sapwood and when it's thin enough to start bending heat treat it.