I'm not sure if it is worth reporting a formal bug for this one.
I found out SMW_GlobalFunctions.php tests for 'SMWRAPStore2' at line 591.
However, SMW_Settings.php defines 'SMW_STORE_RAP' as "SMWRAPStore" at line 340.
As a result, enabling SMW_STORE_RAP throws PHP errors about missing classes for RAP. Using SMWRAPStore2 for the definition for the constant seems to be working.
- Laurent Alquier