Looks like bug 311090, too. The problem with https://bugzilla.mozilla.org/js/ productform.js is reported in bug 311104.
Thanks for reporting that info, Erik. Since both bug 311104 and bug 311090 have been fixed with checked in patches, I'll check again the webpages with tomorrow's build.
Everything works as expected with Seamonkey 1.1a rv:1.9a1 build 2005100505 Resolving as FIXED