Juergen,
I have checked your web site.
In my Javascript Debug Console, I got the following error message:
SyntaxError - Parse error
https://secure.enodis.cc/aspnet_client/system_web/1_1_4322/WebUIValidation.js
It looks the files under you aspnet_client are corruputed.
asp.net Chat http://cutesoft.net/ASP.NET+Chat/default.aspx
Web Messenger: http://cutesoft.net/Web-Messenger/default.aspx
asp.net wysiwyg editor: http://cutesoft.net/ASP.NET+WYSIWYG+Editor/default.aspx
asp wysiwyg html editor: http://cutesoft.net/ASP
asp.net Image Gallery: http://cutesoft.net/ASP.NET+Image+Gallery/default.aspx
Live Support: http://cutesoft.net/live-support/default.aspx