I wonder if your picture cache is large enough in your configuration settings?
 
It also sound like one of the picture cache files is corrupt. I would move them all to another folder (just in case) and reload your project. The waveforms should get redrawn correctly and new picture cache files created.
 
Regards,
Dan

Dan, Much appreciated, although I am going to have to do some research to find out how to do this.
 
1-Just to be sure I understand, everyone talks about the Picture Cache but I don't have a folder called that.  I just have one called Cakewalk Projects | Pictures. And it is on D and the tech is insistent my Picture Cache should be on C  So, want to be sure I know what folder we are talking about.
 
2-Is the cache size set in Preferences?
 

The picture cache is whatever folder is specified in Preferences > File > Audio Data "Picture Folder". The size of the cache is determined by the value of PicCacheMB in Preferences > Audio > Configuration File. To see Configuration File make sure to select the Advanced radio button at the bottom of the Preferences Dialog. The Configuration File data is stored in AUD.ini.

Also please review post #16 which links to the documentation.

Excellent!

I just read another post that talked about crashes using Dim Pro x64.  The project that started this thread had a Dim Pro track.  I used it to replace a Fantom VS track that had missing audio.
 
I wonder if Dim Pro made things worse? For the record it was just a synth pad with three-note chords.

I had the dreaded x64 Dim Pro crash problem but have since resolved it (I think). Am checking with the folks at Cakewalk because it appears to be related to Windows issues, not Sonar issues. I sort of stumbled on the solution by accident when fixing a Windows-related problem, and Dim Pro 64 worked magically afterward. If I really did find a solution and it's not just coincidence, I'll post about it. 
 
Meanwhile, you can try installing the 32-bit version. That's what I did when the crashing was interfering with completing a project; the 32-bit version worked fine. Now that the 64-bit version is working I removed the 32-bit one.

OK, time to start recreating my work in an older version of the project.
 
1. The PicCache was on D, not on C as I was told.
2. The size was set in the configuration file as 500 MB.  The file on the disk was bigger than that. (How?)  I changed the size to 1500.
3. I unfroze all the frozen VIs.
4.  I deleted Dim Pro, in case that was the issue.
 
The project will play about one third of the way through before it stops and Sonar locks up.

Did you ever try archiving the tracks, turning each one on one at a time, and seeing if/where the project stopped?

Craig, I'm sorry, I did not only because it seemed very time-consuming given the number of tracks.
 
Now, however, I am curious and will check that out.  I did not overwrite the problem version so I can still analyze it.  Infact, I'm going to do that right now.