This is not a big one, neither can I tell you which FK themes have these errors in the .css. It doesn't stop them from working, but FF spits them out as errors and ignores them.
This is from FK Pirates.
.rounded_line_ext - never seen this before.
border: solid 1px 1px 1px 1px #34373b;
.row5, .row5h - This line is a duplicate of the correct syntax anyway - So can be deleted.
border-bottom: 1px solid # border-top: 1px solid #ede2bd;