After installing SurferEQ 2.0.5 or SurferEQ Boogie 1.0.5 it still uses the previous version installed (newer than 2.0.5 or older than).
Please manually remove the SurferEQ AAX.
It is located in your AAX Plug-Ins folder:
This can be accessed by the View menu in your finder and Go to folder..
Note: This doesn't affect Windows.