The problem is caused by associating .vbs files with a program other than Microsoft Windows Based Script Host (the default). In my case, I had associated the files with Notepad++. I was able to solve it by running Notepad++ as an administrator and removing the file association for .vbs files.
If you’re not sure which program is causing the problem, you can find out by searching for “Change the file type associated with a file extension” from the start menu. To fix the problem from there, make sure that .vbs files have Microsoft Windows Based Script Host set as the current default program.