This is not as cut and dried as you might immediately believe.
Bankruptcy can discharge your obligations under the promotional agreement. However, a personal services agreement, such as you describe is "executory" under the bankruptcy code, meaning that it hasn't been completely performed by the parties. Because the agreement may have value to your creditors, as a whole, the bankruptcy trustee has discretion to either reject or confirm the contract.
So, it's possible that if there is something in the contract of immediate value (like a fight in the next 90 days, or some public appearance that you would have to have made), then the trustee might attempt to negotiate a confirmation of that portion of the contract, and then reject the remainder.
But, if this is a case of a promoter signing you up and then just sitting on you like you were inventory, then the contract will be discharged and you will be off the hook.
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