Some messages in the Administrator lack contrast and are not easily readable. For example, if a cancel message is displayed, the Product record cancelled text is rendered in a dark color (#000000 for the Bluestork admin template and #2C2C2C for the Hathor template) over the background image (/images/admin_ui/tabs-ul-background.png). It's dark text on a dark gray background.
The black text color is set at line 62 of the /administrator/components/com_virtuemart/assets/css/admin_ui.css file. It should be changed from #000 to #FFF. That is sufficient for the Bluestork admin template but an additional change is required because the Hathor color selector overrides the Virtuemart CSS selector. (See line 1809 of the /administrator/templates/hathor/css/colour_standard.css file.) In order for the Virtuemart CSS to control the color of the message text, it must be more specific than the Hathor selector. Therefore line 62 of admin_ui.css should begin with #system-message-container #system-message dd.message ul.
Virtuemart Version 2.0.9b, Joomla 2.5.6, Site Template: Beez 5, Admin Templates: Bluestork and Hathor