Rob,
I've never used that validator before for CSS. There are issues coming from just about every CSS file on your site. The sourcecoast ones are just at the top. Others large sections of errors come from system.css, general.css, k2.css, template.css and many, many more.
I'm honestly not sure what all the errors mean, but at least a few that I looked at about parsing don't seem accurate. Additionally, browsers, which are what interpret the CSS, don't seem to be throwing any errors when I view the page looking at the developer console.
I ran a few different sites through that tool, some that use JFBConnect and a few 'popular' sites and they all came back with many thousands of messages. Not sure what that tool is really helping to fix, but I can't imagine its possible to fix them all.
Can you let me know if you are seeing any functional errors or issues on your site with display issues?
Thanks,
Alex