Oops - evidently there is a fix to the fix!
Apple released a major patch (Security Update 2005-007) on Tuesday which addresses many issues under Mac OS X components.
Unfortunately the patch causes a break in 64-bit applications. Please see: http://www.macfixit.com/
A successor patch exists which corrects this problem.
Apple's download site can be found here with V1.1 revisions:http://www.apple.com/downloads/macosx/apple/