I have taken some .wav files from a video project timeline and placed them into X3 to complete some audio edits.  The end result of this is not to put it back into the video application, but rather to burn a CD of this final edited audio track.  The .wav files are imported as 48000/16, but in order to put the final mix on CD, I have to export the audio as 44100/16 using pow-r3 dithering.  Once that .wav file is exported from X3, it will not play.  Windows Media Player gives an error.  VLC Media Player shows the progress bar moving but there is no audio.  Sony Sound Forge actually shows the wave form and plays the clip but it sounds as though a high pass filter on steroids was added to the audio, almost like that telephone line frequency effect.  Just to be sure, I burned the file to a CD and got the same results.  What happened to my audio file?  Thanks for everyone’s input.

What is pow-r3 dithering?
There are dithering options in the export pop-up (X3a basic here) but I don't see that one.
Have you tried exporting without the pow-r thing?
Also, this forum is for older Cakewalk software; the X series has it's own forum and many more people read that forum.
 

The dithering options are a feature of all Sonar producer versions. I have it with 8.5 Producer but not with X3 Studio. 
 
If you own Sound Forge why don't you do your wave editing with that? Sonar is kind clunky for editing  stereo wave files. You'll have better tools in SF. As well as proper file handling.
 
This sounds like your issue is with 48 converted to 44.1. 
Dithering is for word length not clock rate
Most audio software work with 32 bit floating point and then you export to 16 bit for CD. This 32 to 16 bit is where dithering does it's mysterious magic to fix errors or something I'll never under stand. 

It is not the choice of dithering algorithm. The pow-r algorithms are included in SONAR producer. Although the description of the export sounds correct, I would expect it was not performed as described. Difficult to tell exatly what went wrong during export. Maybe more details about the exported file would help.
 
FWIW, although any version of SONAR Producer would have similar options, this is not the X series forum. Questions about the X Series are better posed in the forum above this one. This forum is for older versions of SONAR.

Thanks to all three of you for your input. I have spent the last three + frustrating hours working on this problem, generating a total of 16 exports with various settings.  (It was correct that dithering was not needed because I was going from 16 bit to 16 bit).  I went back to old project files and even created a short brand new file with just Sonar instruments.  All results were the same.  Media players could not play ANY of the files.  Something much bigger was going on here.  I couldn't even get audio to play from online You Tube videos simply from my browser.
 
Now I only wish I could give you an answer but it's all working again.  Apparently, nothing on the export screen was causing the problem.  My Focusrite external sound card may have had something to do with it but why would that cause an error on Windows Media Player?  I can only take guesses but rather than spend any more time trying to figure it out, I need to get back to work.
 
Why was I using Sonar instead of Sound Forge?  This project was taking the audio from 3 separate video camera mics (each one mono) at a concert and putting each one on its own sonar track.  I then EQ'd and compressed each one as needed and combined them resulting in a semi-stereo file.  I'm not familiar enough with Sound Forge to go beyond the basics.  I need to learn that application right after memorizing the Sonar User Manual.
 
Also, thanks for mentioning that I should have made this post in the X series forum.  I appreciate your time.

Is WMP or other Windows apps running through the Focusrite? If so, things to look for are sample rate mismatches between the applications, Windows config, SONAR config and the interface. Also driver sharing could be an issue.

The funny thing was, I had just successfully completed an export a couple of days prior, and then with this project it wouldn't work.  And as I said, none of the older projects worked either.  I have no idea what caused the change.  By the way, the telephone line effect while playing the file through Sound Forge was from the audio playing through my video monitor speakers.  The audio wasn't coming through my near-field monitors.  The volume control on my Focusrite had no effect.  So I disconnected and reconnected the usb cable and everything fell back into place.  I just can't place what caused the problem to begin with.
 
Like I said...back to work.  Thanks again everyone.

Oh , that's different. What happened is you lost your ASIO drivers.
 
Check "share drivers with other programs" 
 
If you still loose your Focusrite then you my have to disable the on board or video card audio completely. 
 
With my set up I cannot use Windows Media player at all for playback. I just use Win Amp which seems less fussy about audio drivers. 
Ya Sound Forge is great for just stereo work which I thought you were doing, Sonar is defiantly the best for multi track. 
The cool thing is they will both share some of their plug ins. 
I use the "tool copy" function to open the tracks in Wave Lab if it needs a lot of editing. I find it faster working with those tools as most are only one mouse click. .