Errors in the JS

In the local server, all working good. But when deploy the host server we have errors in the JS. Firebug say "Sys is not defined". When i go to administration and etc.
In Dashboard:
Code: Sys.WebForms.PageRequestManager...
line 52, 424.
And other pages have this error.
Why variable sys is not define in host?
nopCommerce version 1.8
Host:
Microsoft Windows Server 2008 R2 Ent. Ed. (IIS 7.5)
Microsoft SQL Server 2008 R2 Ent. Ed

I need help . :( I find few topics in the forum, but it not solution of  the problem.
http://forums.asp.net/t/1040236.aspx
http://forums.asp.net/t/1040259.aspx

The solution here.