C:\Program Files\Microsoft SQL Server\90\Shared
Change Name of RS Instance name,
1. Go to above mentioned location
2. Open the MOF file in Notepad
3. Search below code and replace string to SQL Server NAME.
#pragma namespace ("\\\\.\\root\\Microsoft\\SQLSERVER")
instance of __Namespace
{
Name = "MSSQLSERVER";
};
4.Save the file, and then exit Notepad.
5.Open a command prompt, and then move to the same folder.
6.Type mofcomp reportingservice.mof, and then press ENTER.
This will solve invalid name space issue