AHP is Ver. 3.228. SDK is the most current version as far as I know.
The SDK was updated a while ago, and it broke compatibility with the older versions of AHP.
I didn't see anything about you having upgraded to AHP 3.306, which is compatible with the latest SDK.
You should try updating your AHP to 3.306, and seeing if that fixes the issue.
As another test, can the CM19A control ANY of your lights directly, using a TM751 to take the RF signal, and pass it to the powerline?
Can you control the CM19A from AHP, and send commands that are picked up by the TM751's or the CM15A?