TypeError: Argument must be a string

[thejsj]

root@8a027b4008b6: node /rethinkdb-proxy/index.js                                 

/rethinkdb-proxy/lib/buffer-parser.js:35                                          
        if (Buffer.byteLength(this[_queue_]) >= 4) {                              
                   ^                                                              
TypeError: Argument must be a string                                              
    at BufferParser.append (/rethinkdb-proxy/lib/buffer-parser.js:35:20)          
    at Socket.<anonymous> (/rethinkdb-proxy/lib/index.js:171:23)                  
    at Socket.emit (events.js:95:17)                                              
    at Socket.<anonymous> (_stream_readable.js:765:14)                            
    at Socket.emit (events.js:92:17)                                              
    at emitReadable_ (_stream_readable.js:427:10)                                 
    at emitReadable (_stream_readable.js:423:5)                                   
    at readableAddChunk (_stream_readable.js:166:9)                               
    at Socket.Readable.push (_stream_readable.js:128:10)                          
    at TCP.onread (net.js:529:21)                                                 
Exited with code: 8