Ah … spotted the specific exception by going back to Nabble. I was just looking for reasons why it might not compile. :)

To be honest the line:

… looks wrong. I can't work out a way in which it could compile, even if I assume that the code is missing imports of either a POC_CombineString function or class. However, again, it wouldn't give the specific "mismatched input 'from'" exception claimed.