I'm currently tasked with developing a branding solution for SharePoint Foundation sites. I've created a WSP file which can be deployed through my local machine through Visual Studios, but when I upload the solution into the Solution Gallery in site settings, I can't activate the solution. The solution was created as a sandboxed solution according to this article.
When I choose to activate from the RibbonMenu or the drop down for the solution, the resulting modal dialog has an activation button which is disabled. I'm logged in as the System Account, so I believe I have full permissions over the site collection.
What do I need to do in order to activate solutions from this gallery page?