Appearently your stp configuration does not handle this setup correctly. In stp configs like yours, the 2912 should be the root of the spanning tree. If it is not, please reconfigure spanning tree by assigining a sufficiently low priority to the 2912.
(command: spanning-tree vlan XX prio 4096)
If this is changed, you will probably see that one of the ports that's connected to the wireless bridge will go into blocking state.
Besides al this, I cannot see the goal that you try to achieve with this setup. Wireless bridges are typically used to link two networks that are not otherwise connected and for redundancy I would never use a wireless connection if a wired one is available. Anyway, good luck with your setup
Regards,
Leo