Created a new F5 partition -- now I'm getting an exception with my iControl automation (java api)

I don't know what you code looks like, or java that well, but it appears you are trying to utilize a node that was created in Common and you are in PC3. You will need to specify the partition of the Node in your code if you plan to make these changes from the PC partition. /$partition/$node_ip

Or create all nodes in the partition they will be used in.

Hopefully, you created partitions for a good reason. I have found them to be something you use only when you must, as they increase operational complexity greatly.

Hope it helps!

D