If you are seeing this error when trying to compare two documents/versions with Workshare 9 (or higher)...
"c:\program files (x86)\workshare\modules\DeltaVw.exe
The system cannot find the file specified.
...it may be because you are using the old Workshare integration rather than the new one.
The old integration will be named "Workshare" on the Send to Application menu, while the new one is called "Workshare Compare":
To enable the new integration, go to the Cabinet Administration page and then click the "Integrate External Applications" link at the top. Select "Workshare Compare" to enable the new integration. Workshare has these instructions on their install guide linked here: Setting up the Workshare Integration.
Removing the Old Workshare Integration
If you want to remove the old integration, deselect the "Workshare" option under the "Local Applications" section at the bottom of the "Integrate External Applications" page: