If I get it right, the CQ-18T will be “main” device, connected wirelessly with the mAp, and the mAp connected via ethernet cable to the Driverrack.
From what I can understand, the CQ-18T works as Access Point.
This means that the mAp needs to be configured as client, i.e. in Mikrotik jargon, as station.or CPE.
So the base should be your version a.
Try returning to your (only partially) working version a, then follow these instructions and post your configuration:
http://forum.mikrotik.com/t/forum-rules/173010/1