Can I find a list of all of the error codes and their meanings which a bitcoin node can return when using the RPC commands?
Here is the list inside the Bitcoin Core v0.15.0.1 source code:
https://github.com/bitcoin/bitcoin/blob/v0.15.0.1/src/rpc/protocol.h#L32L87
not to easy, you might want to read the code:
https://en.bitcoin.it/wiki/Original_Bitcoin_client/API_Calls_list#Error_Codes