A weird one, if you cannot launch the EXPORT process. Try launching Videopad itself it by right-clicking and clicking RUN AS ADMINISTRATOR.
Remember, there must be at least one clip on the timeline, or there will be nothing to export.
If no joy, perhaps the program did not correctly install.
Back up your project to an independent folder, using FILE|SAVE PORTABLE PROJECT. This will store all the project files and the VPJ data file.
Go to PROGRAMS AND FEATURES and UNinstall Videopad. Then install the latest version.