i am running OS - Windows 7
You haven't said if you use 32 or 64 bit, and there's a difference regarding to registry keys, as I've indicated in my previous message.
Okay - i have a problem that the sceneries are not being added automatically to the Scenery Library - but where is the problem 
everything else is running fine - only the FS Dreams products not.
"running fine" doesn't mean much, depending on what your other addon installers are trying to do.
Do you mean you have other addon sceneries that are supposed to automatically add their area to the Scenery Library using their installer which installs and successfully add their area to the Scenery Library automatically, and only the FSDT scenery installers fail to add the scenery to the Scenery Libraray automatically ?
Or, do you mean they just runs fine, but they don't need to interact with the scenery.cfg, so it's not really relevant to this issue anyway ?
It's possible you configured FS9 to run into any of the XP Compatibility modes ? This is wrong and shouldn't be used, and it also affect the location of the scenery.cfg in use. The scenery.cfg is located in different places, depending on the OS, it can be both in the FS9 root folder (as in XP) OR in the %APPDATA%\Microsoft\FS9 folder (as in Vista\Win7 )
Our installer automatically updates BOTH locations of the scenery.cfg, the XP location and the Vista/Win7 location so, this shouldn't be an issue.
However, if on top of running FS9 in XP mode, you also installed it into the default C:\Program Files (or in the C:\Program Files (x86 ) under a 64 bit OS), under Vista/Win7 there's no write permission on this folder. Which is why the scenery.cfg in Vista/Win7 resides in %appdata% but if the XP mode moves the location of the scenery.cfg to the FS9 root folder, the installer can't modify it.
You should check if your are running FS9 into XP compatibility mode (or any of the compatibility modes) and turn it off, the run all our installers again.
As a general suggestion, it's best NOT to install FS9 or FSX into the C:\Program Files default folder under Vista/Win7 but, instead, use a folder you specify, like C:\FS9. This way, you don't have any permission problems from any addon installer that need to modify any of the configuration files.