events.js:141 - throw er - Unhandled 'error' event

[mobarra]

$gulp build
[14:03:06] Using gulpfile C:\xampp\htdocs\sample-app\gulpfile.js
[14:03:06] Starting 'wiredep'...
[14:03:06] Wiring the bower dependencies into the html
[14:03:06] Starting 'clean-styles'...
[14:03:06] Cleaning: ./.tmp//*.css,./build/styles//.css
[14:03:06] Starting 'clean-code'...
[14:03:06] Cleaning: ./.tmp/__/.js,./build/js//*.js,./build//.html
[14:03:06] Starting 'vet'...
[14:03:06] Analyzing source with JSHint and JSCS
[14:03:07] Starting 'clean-images'...
[14:03:07] Cleaning: ./build/images/__/.*
[14:03:07] Starting 'clean-fonts'...
[14:03:07] Cleaning: ./build/fonts//.
[14:03:07] Finished 'clean-images' after 30 ms
[14:03:07] Starting 'images'...
[14:03:07] Compressing and copying images
[14:03:07] Finished 'clean-code' after 1.38 s
[14:03:07] Starting 'templatecache'...
[14:03:07] Creating an AngularJS $templateCache
[14:03:07] Finished 'clean-styles' after 1.48 s
[14:03:07] Starting 'styles'...
[14:03:07] Compiling Less --> CSS
[14:03:08] Finished 'clean-fonts' after 729 ms
[14:03:08] Starting 'fonts'...
[14:03:08] Copying fonts

events.js:141
throw er; // Unhandled 'error' event
^
Error: spawn C:\xampp\htdocs\sample-app\node_modules\optipng-bin\vendor\optipng.exe ENOENT
at exports._errnoException (util.js:870:11)
at Process.ChildProcess._handle.onexit (internal/child_process.js:178:32)
at onErrorNT (internal/child_process.js:344:16)
at nextTickCallbackWith2Args (node.js:442:9)
at process._tickCallback (node.js:356:17)