Hello,
The 32-bit and 64-bit SSC modules have the same inputs (they are based on the same code), so I don't think that is what is causing the problem. It is more likely that you are looking at a different version of SSC in the SDKtool than you are using with MATLAB. To ensure you are looking at the same version of SSC, start the SDKtool, and then click the "Choose SSC library" button and navigate to the copy of ssc.dll that MATLAB is using. (Note that you'll need to use the 32-bit version of SDKtool to read the 32-bit version of ssc.dll, and likewise for the 64-bit version.)
You can also use the variable documentation functions as described in Section 3.4 of the SSC Guide that comes with the SDK to list all of a modules variables from your code.
What is the pvwattsv1 variable that the error mentions?
Best regards,
Paul.