Hi Dave,
Not really much information to go on here, sorry. Probably what I'd do first is use Firefox and Firebug to determine the error in the console, and then move forward from there.
BTW - you're using a really old build of NetTalk and an epically old build of Clarion, so you might find you have fewer problems if you upgrade both of those. I recommend Clarion 9. We don't support Clarion 6 anymore, so you're gonna find updates hard to come by if you stay there.
cheers
Bruce