Please change the url of the upload link in the toolbox, so set the following line under wgUploadNavigationUrl:

'incubatorwiki' => 'http://incubator.wikimedia.org/wiki/Incubator:Upload',

That way it goes to [[incubator:Incubator:Upload]], a page containing more information how to upload on Commons (locally disabled for non-bureaucrats), otherwise they see only a sentence "restricted to bureaucrats".

I started a talk on http://incubator.wikimedia.org/wiki/Incubator:Community_Portal#Upload_page but, as we're a small community, no one reacted. And this does not really needs a community consensus.

Version: unspecified
Severity: enhancement
URL: http://incubator.wikimedia.org/wiki/Special:Upload