Hi Bruno,
There was a bug in CE 2014.0 which prevented displaying attributes of imported cga files in the inspector.
The error you see is connected to that bug.
However, the rpk "works", i.e. the model is generated as expected.
The bug is fixed in CE 2014.1, I just verified it with your rpk. CE 2014.1 will be released very soon.
regards
Matthias