Watchman errors on app start after upgrading to 0.4.0

Getting multiple errors at app start after upgrading an existing app from 0.3.11 to 0.4.0.

Using 0.3.11 everything is fine.

First, when running cmd + R from Xcode, this error is appearing in the packager window:

 ERROR  Watcher took too long to load
Try running `watchman` from your terminal
https://facebook.github.io/watchman/docs/troubleshooting.html
Error: Watcher took too long to load
Try running `watchman` from your terminal
https://facebook.github.io/watchman/docs/troubleshooting.html
    at null._onTimeout (/Users/mikewilcox/code/randUM/node_modules/react-native/packager/react-packager/src/FileWatcher/index.js:74:16)
    at Timer.listOnTimeout [as ontimeout] (timers.js:112:15)

so then followed and tried to npm start from the shell and got this:

Error: watch EMFILE
    at errnoException (fs.js:1030:11)
    at FSWatcher.start (fs.js:1062:11)
    at Object.fs.watch (fs.js:1087:11)
    at NodeWatcher.watchdir (/Users/mikewilcox/code/randUM/node_modules/react-native/node_modules/sane/src/node_watcher.js:144:20)
    at Walker.<anonymous> (/Users/mikewilcox/code/randUM/node_modules/react-native/node_modules/sane/src/node_watcher.js:351:12)
    at Walker2015-04-17 19:42 node[25755] (FSEvents.framework) .emit (events.js:98:17)
    at /Users/mikewilcox/code/randUM/node_modules/react-native/node_modules/sane/node_modules/walker/lib/walker.js:69:16
    at Object.oncomplete (fs.js:107:15)
FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-21)

See http://facebook.github.io/react-native/docs/troubleshooting.html
for common problems and solutions.
2015-04-17 19:42 node[25755] (FSEvents.framework) FSEventStreamStart: register_with_server: ERROR: f2d_register_rpc() => (null) (-21)

[mwilc0x]

Just to update how I solved this:

brew uninstall watchman
brew link automake
brew install --HEAD watchman

Cheers

[doukasd]

I did not have watchman installed (new pc). So the solution for me was just:

brew install watchman