I isolated the problem and found what I did.
I have two PGN 61445 modules each with different 'Source' Address and the 'Use Source' set to True for both of them.
This worked and I had no problems.
Recently I changed one of 'Use Source' to False, and it caused this error.
Makes sense why it doesn't work, but it was a pain to track down, hopefully you guys can add something to the compiler error messages that would help the next guy that makes a similar mistake.
Thanks,