ubuntu 14 start error

[XeniumNetwork]

/blockchat# node chat-node.js
starting blockchain interface on port 3000...

    chain state : http://localhost:3000/state
    transactions: http://localhost:3000/txs

Please report the following error as a Github Issue on:

    Please report the following error as a Github Issue on:
    https://github.com/devslopes/blockchat

Possibly Unhandled Rejection at: Promise Promise {
{ Error: ENOENT: no such file or directory, open 'priv_validator.json'
at Object.fs.openSync (fs.js:646:18)
at Object.fs.readFileSync (fs.js:551:33)
at Lotion (/root/blockchat/node_modules/lotion/index.js:63:19)
at main (/root/blockchat/chat-node.js:68:15)
at Object. (/root/blockchat/chat-node.js:131:1)
at Module._compile (module.js:652:30)
at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
errno: -2,
code: 'ENOENT',
syscall: 'open',
path: 'priv_validator.json' } } reason: { Error: ENOENT: no such file or directory, open 'priv_validator.json'
at Object.fs.openSync (fs.js:646:18)
at Object.fs.readFileSync (fs.js:551:33)
at Lotion (/root/blockchat/node_modules/lotion/index.js:63:19)
at main (/root/blockchat/chat-node.js:68:15)
at Object. (/root/blockchat/chat-node.js:131:1)
at Module._compile (module.js:652:30)
at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
errno: -2,
code: 'ENOENT',
syscall: 'open',
path: 'priv_validator.json' }
Trace
at process. (/root/blockchat/chat-node.js:128:13)
at emitTwo (events.js:126:13)
at process.emit (events.js:214:7)
at emitPendingUnhandledRejections (internal/process/promises.js:108:22)
at runMicrotasksCallback (internal/process/next_tick.js:124:9)
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickCallback (internal/process/next_tick.js:180:9)
at Function.Module.runMain (module.js:695:11)
at startup (bootstrap_node.js:188:16)
at bootstrap_node.js:609:3