I am thinking maybe after applying the upgrade that you might have to re-authorize Spark outside of Sonar, and then I think it might start working.
The above is speculation, but I do recall scan issues in the past, and I think that once control is passed to the dll, that Sonar may have to wait for it to respond, so if there is some sort of internal issue that the dll doesn't know what to respond with, (like not being authorized), it might then appear to hang.
That might actually be a dll-caused issue.
So, I suggest you check out the authorization of Spark, and see if that clears it up.
Bob Bone