Warning: Path must be a string. Received undefined Use

[hagenbauer]

I may be blind but I cant see my error
This is my gruntfile for webfonts

grunt.initConfig({
  webfont: { test1: {
				src: '_icons/*.svg',
				dest: 'fonts',
				options: {
					hashes: false
				}
}}});

This is my dir tree

├── assets
├── css
├── fonts
├── _icons
├── _includes
├── js
├── _layouts

But I always get this error and I cant see what path is wrong

Running "webfont:test1" (webfont) task
Verifying property webfont.test1 exists in config...OK
Files: _icons/glyphicons-196-circle-info.svg, _icons/glyphicons-517-menu-hamburger.svg, _icons/glyphicons-social-13-xing.svg, _icons/glyphicons-social-23-youtube.svg, _icons/glyphicons-social-32-twitter.svg, _icons/glyphicons-social-38-rss.svg, _icons/glyphicons-social-40-e-mail.svg -> fonts
Verifying property webfont.test1.src exists in config...OK
Verifying property webfont.test1.dest exists in config...OK
Options: hashes=false
Warning: Path must be a string. Received undefined Use --force to continue.

Aborted due to warnings.

[alampros]

Did you try running grunt in --verbose mode?

[hagenbauer]

yes. this is --verbose