Hi , I suspect what has happened is you have previously downloaded and installed the minimum installer package of PhotoVidShow and then tried to install the full install package of PhotoVidShow. Windows installer does not like these situations and reports an error as you mentioned. The simplest solution is to first un-install PhotoVidShow, then re-install from full version. See here to un-install
The minimum/full versions are actually identical software, but the full version does not need to download media files for some of the slide design templates and backgrounds (if you use them of course).