Hi
You should be able to export your project with any version of VP although the free version will have limited export options. I would uninstall (Completely) all references to VP from your PC and then download the most recent version (6.10) from the NCH download page.
https://www.nchsoftware.com/videopad/index.html
If you still have the original version 5.03 .exe file you could also reinstall THAT version if things still don't work out.
Nat