I don't suppose anything notable changed between 5.3 and 5.5 in the way Guvnor loads data enumerations?

I have a number of enumerations similar to the following:

'MyFact.currencies' : (new com.myapp.guvnor.enums.CurrencyEnum()).isoCodes() 

But I see the exception in Guvnor:

The jar is in the lib directory, there is a method called "isoCodes()", and when I run the main class inside it then the various enumerations are returned. And yes, it did (does) work absolutely fine in 5.3 with this same configuration.

Steve