It appears that you are running Windows XP, which could be the issue.
If the following files already exist then skip this...
If Videopad loads, but simply won't allow import of files download (removed) and copy it to this "VideoPad" folder...
"C:\Program Files (x86)\NCH Software\VideoPad" (or similar, without the X86)
Next create a new folder named ffmpeg23 under the "Components" folder that's in this path...
"C:\Users\<PC Name>\AppData\Roaming\NCH Software\Components" 
To do that, open the Components folder. Right-click in a blank area and click NEW | FOLDER and name it ffmpeg23
Download (removed) into that new ffmpeg23 folder.
If still no joy you might try installing older VP versions from here.
Beyond those suggestions, another PC with an up-to-date operating system may be your next move.