Hi,
You may try the steps below:
Uninstall VideoPad, then delete 3 folders named "VideoPad" and 1 named "Components" from these locations:
**C:\Users\<username>\AppData\Roaming\NCH Software\VideoPad\
**C:\Program Files (x86)\NCH Software\VideoPad\
**C:\Program Files (x86)\NCH Software\Components
**C:\ProgramData\NCH Software\VideoPad\
**If you can't find any of the folders, just continue.
When this is done install the software one more time and try with different output format.