The problem resides with the WIX compiler that is used by Gen. But, it turns out that the assembly actually does complete, the error message notwithstanding. The .msi file is usable and has no errors when deploying it.
For the Product Name of all numerics, add a alpha character to the number. For instance, if the Product Name used is 5555, use 5555x instead and the WIX error will not occur.