Please be sure that you have not moved the program and/or database to a lock device, like a USB key.
First make sure you've logged into the computer with a user that has enough permissions.
1. Set to run as AN administrator (Right click > Properties > Compability tab > Mark "Run this program as an administrator). It will then not be ran as the specific user "Administrator", but with admin Privilegies.
2. Set the security settings to Full Control on the application. (Right click > Properties > Security tab)
You can also try to delete any old Desktop program folders from past version, then delete any old backup files in the v1-4 folder, then maybe reset the frequency of backups within the Setup section. This would free up some space.
A final option to try:
1) Quit the WebExercises program
2) Locate the 'WebExercises Desktop v1-' folder, should be in the 'Program Files' folder
3) Right click on the folder and select Properties
4) Make sure the 'Attributes: Read-only' is not checked (see screen shot), click the box a few times until it is clear/empty
5) Click Apply
6) If a 'Confirm Attribute Changes' dialog comes up, select 'Apply changes to this folder, subfolders and files' and click OK
If you still get the same error, open the 'WebExercises Desktop v1-' folder and repeat these steps on the 'WebExercises Desktop v1-' program file and the 'WebExercises_Database_v1-4' file.