I know this isn't much comfort to you, but I get that problem on your site in Safari 5.03 using OSX, but my site also uses striking and I don't get this happening.
Again, i've tested your site using Safari 5.0.3 for OSX and I see the problem you are having but I don't see the problem on my own site using Striking.
Interestingly it works fine as it is loading but when the site is completely loaded you get the CSS problem.