The line number is not relevant because it simply points to the place where the exception is thrown, but that's not where the problem lies as the null->NaN value is coming in as a parameter to that method.
The stack trace would actually show the bad call, I'm trying to imagine why is missing.

In the library there are many calls to (a method that calls) that method, that's why pinpointing the case with static analysis of the code is not easy. Unfortunately it looks like at this point is the only path left.

Just to try and reduce the code to be analyzed, does your application use our visual widgets?