Error: Webform_DoPostBackWithOptions is not defined
Source File: Webform_DoPostBackWithOptions(new Webform_PostBackOptions("dnn$ctr327$HostSettings$cmdCache", "", true, "", "", false, true))
Line: 1

On my DNN install 4.8.2     my module settings and as well as host settings I can't update anything or use any button with a Webform_PostBackOptions  javascript in in.

for example __doPostBack('dnn$ctr370$ModuleSettings$cmdCancel','')  works fine.

Other related error is :   Sys is not defined refering to   Sys.Webforms.PageRequestManager._initialize('ScriptManager', document.getElementById('form'));

I am wondering if a script or library is not loading properly but I do not know how to trouble shoot this.  Any one experience this?

Be sure .AXD files are mapped to .NET 2.0 instead of some other version you may have installed on that system.  I had this problem crop up after installing some Visual Studio tools, and while my .ASPX files were still properly associated with .NET 2.0, my .AXD files had reverted to .NET 1.1.