I think if you try to use this package via R nodes in KNIME it would call a local JRE version and this is what may cause the problem.
You could try to updated your local Java version or try the python based solution.
I was trying to get a solution in R working but ran into several problems. And yes I know that R is easier to maintain than python. But if you want to decrypt Excel files you might give it a try.
BTW the short story to install python with KNIME is here:
You might skip the deep learning part. The official guide is here: