Something has happened with the indexes in your WinMORE. You need to re-build your indexes. If you have a network version of WinMORE, make sure everyone is logged out except you.
In WinMORE:
1. Click Setup and click Re-build Associate-TAX ID Index.
2. Close down WinMORE.
3. Once you re-open WinMORE, it should work fine.
If the error persists, please send a ticket to MCA Support by completing this form with the correct associate's WinMORE profile - Associate tab and Commission tab, the Commission request with all details, and the DA attached.