@kidsinglish productions, 
 
I DO understand your confusion with the installation process for X3.  There are quite a few pieces to it.
 
Here is a link from the Cakewalk site, that contains download instructions for X3:
 
http://www.cakewalk.com/Support/Knowledge-Base/2007013359/SONAR-X3-Download-Installation-Instructions
 
Please note that at the bottom of the above link's page, there are 3 links for the 3 different versions of X3 that exist, and if you click on the appropriate version, it will expand and list out all of the download files, and will indicate (a little cryptically) which ones to run, and which ones get auto-launched.
 
Once the 01_Read_This_First_SONAR_X3.exe has bin launched, it will create a folder called: 
 
D:\Users\Robert\Downloads\Cakewalk\Sonar X3 Producer Retail\SONAR X3 Documentation
 
Within that folder, you can find SONAR X3 User Guide and X3 Read Me files.
 
The installation programs you would launch to install X3 Producer are:
 
01_Read_This_First_SONAR_X3.exe
02_SONAR_X3_Producer.part1.exe
03_Loops_And_One_Shots.part1.exe
04_Dimension_Pro_1_5_Setup.exe
04_Dimension_Pro_1.5_Expansion_Packs.zip (compressed folder)
 
Contained within the above zipped folder is the installer for the Dimension Pro Expansion packs, and that actual installer name is: 'Dimension Pro Free Expansion Packs 1-3.exe', so you would run this.
 
There are separate instructions for downloading and installing Addictive Drums.
 
In the Read Me document (path is shown above in this post), it instructs you to launch either Sonar X3 or the stand-alone version of Dimension Pro with the EXPLICIT option 'Run As Administrator', in order for the registration codes to properly be confirmed.  The same holds true for proper completion of the registration process for Rapture.
 
Here is the text from that Read Me document:
 
After installing Dimension Pro and Rapture you must either run the standalone applications or SONAR X3 as administrator for Dimension Pro/Rapture to accept the registration number. This can be done by right-clicking on the SONAR icon or the standalone application icon and selecting "Run as Administrator".
 
I hope the above helps you to understand the installation process a bit better.  The forum is also available to help you AS you go through an installation, or are preparing for one, so you can ask whatever questions you wish about what to run and in what order.
 
The same holds true for if you wish to ever do a complete removal of a Sonar installation, in order to either just be done with it or if you want to do what is called a 'clean install' of Sonar, where all prior traces of the previous install are removed from your computer first.  (This might be useful for you, if you want another proper crack at getting the 64-bit X3 version properly installed).  The forum folks can and will walk you through those steps, if you decide to do this, as well.
 
Bob Bone
 

robert_e_bone
By installation default, the paths for these two 64-bit DXi Sonar synths are:
 
C:\Program Files\Cakewalk\Shared DXi\TTS-1
C:\Program Files\Cakewalk\Shared DXi\Groove Player
 

FWIW Bob, a point of correction ...
GrooveSynth is actually under the C:\Program Files\Cakewalk\Shared DXi\P5antom directory - (p5antom.dll).
 
Groove Player does not actually present as a DXi Instrument for me yet interestingly, unlike other DXis, the dll is invoked on Sonar launch (as evidenced via SysInternals Process Explorer). The .chm helpfiles in respective directories give some clues too. My guess was that it's probably the engine/player behind groove clips(?). This fits pretty well with BitFlipper's description here. Further suggestion in that thread is that it's got something to do with Metronome playback.

Thanks - I never use it, but thought it might have been the one I mentioned.  I just thought it went under a different name, as does happen from time to time.
 
I did check the dll to make sure it was indeed a 64-bit version, but did not actually load it to make sure it was the same synth I had indicated it was.
 
Incidentally, Dependency Walker can process a dll, which is how I verified both were indeed 64-bit, and also looked at known 32-bit dll's to verify Dependency Walker's info.  In that middle pane, if you scroll to the right a bit, (no pun intended), you will see a column called CPU, and that will tell you if the dll is 32-bit or 64-bit.
 
I had actually made my initial response directed at TTS-1, and only went back and added the GrooveSynth stuff at the very end of reviewing my first set of post content, just prior to submitting.
 
DOH
 
Anyways, the rest of the earlier post should be in order.  Sorry for any confusion.
 
Bob Bone
 

My bad - last time I'd checked I was right :-)

ShellstaX
 
Groove Player does not actually present as a DXi Instrument for me yet interestingly, unlike other DXis, the dll is invoked on Sonar launch (as evidenced via SysInternals Process Explorer). The .chm helpfiles in respective directories give some clues too. My guess was that it's probably the engine/player behind groove clips(?). This fits pretty well with BitFlipper's description here. Further suggestion in that thread is that it's got something to do with Metronome playback.

I'm almost certain it is used for the metronome, and was added at the time when the audio metronome was first introduced.    Now there's a topic for flashbacks...