When I validate by URI by entering URI into the validator page my css was validating. Later it stopped validating and I got the same not found error as described below [same for the 2nd site].
But, When I attempt to validate from the site http://blackboxnyc.com/soulsearching/index.html I get an error message that 138 errors are found. But I can't find those errors. See http://jigsaw.w3.org/css-validator/validator?profile=css2&warning=2&uri=http%3A%2F%2Fblackboxnyc.com%2Fsoulsearching%2Findex.html
And, when I visit my css page online http://blackboxnyc.com/ui/bbnyc.css and attempt to validate it using the link in FF>tools I get an error message that the page is not found "Target: http://blackboxnyc.com/ui/bbnyc.css

I/O Error: http://blackboxnyc.com/ui/bbnyc.css: Not Found " See http://jigsaw.w3.org/css-validator/validator?profile=css2&warning=2&uri=http%3A%2F%2Fblackboxnyc.com%2Fui%2Fbbnyc.css

When I try to validate by calling up the validator through FF when at the home page for http://blackboxnyc.com I get a report that there are 56 errors, but again, I can't see them and the URI validates fine when I visit the validator page and enter the URI there. See http://jigsaw.w3.org/css-validator/validator?profile=css2&warning=2&uri=http%3A%2F%2Fblackboxnyc.com%2F  
Same error message comes up when I try to validate using ff from the validator link [that page is not found]

When I check another of my sites http://thewei.com the validator works fine.