I'm working with bitcoin-qt to send payments, the config file is set to work with JSON-RPC. it's include the rpcuser and rpcpassword, all calls I make to the wallet works fine, on the UI of the bitcoin-qt.exe I wanted to encrypt the wallet so every send payment I do from the UI will ask me for user password, I did it from setting->encrypt wallet. After that all calls from JSON RPC I get an error "The remote server returned an error: (500) Internal Server Error." . should I add something in the conf file ?