Sys.InvalidOperationException occurs on Lists sharepoint 2010

Sys.InvalidOperationException occurs Error Type: SP.Permissionkind has already been registered in Sharepoint (SP 2010):

Error : Type SP.PermissionKind has already been registered.

The only reason for this error is that some script files included several times in page body.

This error occured while using the javascript client object model ( ecma script ) in applciation page. The solution for this error is that any references of the js files made twice would cause an exception like this.




Problem is in detail,

Had refrence to SP.js file and also using the ExecuteOrDelayUntilScriptLoaded(something, "sp.js"); in my applictaion page.

This caused the "not very explanatory" error.

What to do ?
 
So by removing this scriptlink would help to fix this error.