Hi Steven,
I have one trick that helped me in such a situation. Try this:
1. Close the project in TestExecute.
2. Switch to the machine on which the project is located.
3. Open the folder that contains the project suite corresponding to your project.
4. Find the file with Your_Project_Name.pjs.tcNET (this file is stored in the same folder as the project suite file).
5. Create a copy of this file (just in case) and save it to another folder.
6. Remove the .tcNET file stored in the project suite folder.
7. Open TestExecute and run your test again.
Does this help?