Maya Kaathryn Bohnhoff posted on Bookview Cafe on when to break up with your ghostwriting client, which also applies to editing clients and writer-writer collaborations.
I've never done a ghostwriting job, but I've collaborated on writing projects and I absolutely agree with her that you have to be able to trust your partner. If your collaborator or client starts going squirrely on you, it's time to bail.
Note that Maya was getting paid for her work regardless of whether the books got published, but bailed because she didn't want to deal with the squirrely client, money or no money. Sounds like she made the right choice.
Check it out..