Javascript error

Tammie pointed out a javascript error to me on my site. I have had a look, but am totally out of my depth on this one.

I disabled all my plugins and found that it went away when I disabled mu-plugins. So I took out my mu-plugins one-by-one when I took out moderation_framework.php the error went away and when I put it back, it came back. This is from the Moderation plugin.

I have no idea how to fix this. Here is some additional info:

I get the following information from firebug:

this is the filename: "http://ukmarketingnetwork.com/wp-includes/js/prototype.js?ver=1.6.1"
line number error occurs: 4725
message: ""throw $continue" is deprecated, use "return" instead"
message name:Error
stack:"Error("\"throw $continue\" is deprecated, use \"return\" instead")@:0 @http://ukmarketingnetwork.com/wp-includes/js/prototype.js?ver=1.6.1:4725 "

This is the line in the JS that breaks:
try{convertEntities(thickboxL10n);}catch(e){};

I am using WP 3.01 and BP 1.2.5.2