I completely misread your original question. Thom is correct that your broker's obligation to pay you is established in your independent contractor agreement. My apologies.
Keep in mind however that they can't pay you until they receive money from the coop broker and/or the title company. Be patient it takes some time sometimes to get things run through all of the accounting that must take place.
Section 8-E of the Independent Contractor Agreement you should have signed with your Broker outlines the terms of payment.
You can find a copy of the ICA in WinForms.
Broker - Associate
I am going to go out on a limb and say that this isn't a statutory issue. The binding agreement that you have formed with the listing broker (to pay the commission) is created as a result of the rules of the MLS. I would call your local board of realtors or the MLS office where you both are members and ask them if they have a rule pertaining to the length of time for payment. My hunch is that they don't but I have been surprised before.