ios-webkit-debug-proxy gets disconnected from ipad while running tests

I am trying to run test on physical iPad. I am using appium and webkit-ios-debug-proxy. But ios-webkit-debug-proxy gets disconnected when i try to run tests. It gives an error -

Invalid message _rpc_applicationUpdated: <dict>
<key>WIRApplicationIdentifierKey</key>
<string>PID...</string>
<key>WIRIsApplicationProxyKey</key>
<false/>
<key>WIRApplicationNameKey</key>
...
</dict>
Disconnected 

I found dome forums, where it was mentioned to run from the appium folder, but when I run the command, I get an error -

"module.js: ..throw err Error: Cannot find module 
'underscore' at Function.Module_resolveFuleName (module.js:336:15) .... 

So that solution does not work for me either.