ignore commented out css

I have the following code commented out in one of my css files :

/*
.acLoading {
background : url('indicator.gif') right center no-repeat;
}*/

and getting the following errors:

[main] ERROR resource.ResourceMeta - While processing /bundle-bundle_css_head.css, /css/reset.css, /css/bleep.css, /css/nav.css, /css/modules.css, /css/track_list.css, /css/player.css, /css/jgrowl.css, a resource was required but not found: /css/indicator.gif
[main] WARN util.ResourceMetaStore - Cannot locate resource [/css/indicator.gif]
[main] WARN mapper.cssrewriter - Cannot resolve CSS resource, leaving link as is: resource:/css/indicator.gif

is bug? commented out css should be ignored? ..