Chuckebaby, thanks for the suggestion, but it does not work...
...update... It does not work as suggested. I believe the .wrk and .cwp files are similar enough to be able to interchange the suffix as I have accomplished this with another .wrk file that does work correctly, so the problem is with loading the questionable files into Cakewalk.
While reading through other questions and comments I discovered this hand workaround;
Create a new project in Cakewalk
On the Media browser, change the filter to "Projects"
Navigate to your .wrk file using the Media browser
Drag the. .wrk on to the clips area
Ok, now that I have the actual tracks inserted into the clips pane, I realize that it is the only thing that gets brought in this way. there are no sysex banks, no patch assignments, no effects, nothing but the track data. so although this gets me access to the track data, it still does not fix the problem.
Ok, I might have discovered a solution.
In Preferences/File/Advanced I tried checking the box "Load Non-Cakewalk Files in Offset Mode" . I don't yet know what Offset Mode is, but this appears to have allowed the program to play the old .wrk files.