This problem has absolutely nothing to do with flexibleVM2Global.css. Indeed, this has nothing to with "any" CSS file.
It is because you are loading sharethis.com's JS file and the share buttons in your website without providing sharethis.com's account ID. Don't use sharethis.com's service, but instead use
www.addthis.com to generate share buttons.
I know you didn't do it; but one of the extensions in your joomla is loading sharethis.com's buttons without the account ID and this is the source of the console warning. Find that module to load those share buttons and disable it.
See the screenshot:
Attachment Pasted_Image_9_20_13_5_51_PM.png not found
The initial case solved. Topic is closed for clearance.
Regards.
Support & Development