Cannot read property 'graph' of undefined

[XZ6H]

When I run the boomerang-server using npm start, I get "Cannot read property 'graph' of undefined". The server page "http://localhost:8080/" in my case is accessible but no tasks are shown and the same error message is shown in "http://localhost:8080/client". Can anyone help?

TypeError: Cannot read property 'graph' of undefined
at Ldp.self.get (/home/hemant/node_modules/ldp/ldp.js:154:20)
at Object.Ldp.self.middleware [as handle] (/home/hemant/node_modules/ldp/ldp.js:95:12)
at next (/home/hemant/node_modules/connect/lib/proto.js:174:15)
at Object.handle (/home/hemant/node_modules/express-utils/index.js:54:5)
at next (/home/hemant/node_modules/connect/lib/proto.js:174:15)
at next (/home/hemant/node_modules/connect/lib/proto.js:149:78)
at SendStream.error (/home/hemant/node_modules/serve-static/index.js:120:7)
at emitOne (events.js:115:13)
at SendStream.emit (events.js:210:7)
at SendStream.error (/home/hemant/node_modules/serve-static/node_modules/send/index.js:245:17)