I just installed Splash Lite on one of my Windows boxes and got the same error. After some googling I stumbled upon this thread and the official "advice" given. With respect, this is such cr*p it drove me wild enough to register with this forum to leave a comment here. The only sane way to run a Windows family computer - and I don't give a monkey what M$ thinks - is to install ONE admin account and make everyone else a LIMITED user. After that, turn off UA for some peace and quiet. I have been running our family computers like this for years, going back to XP. The "resolution" offered DOES NOT work on such a configuration because - Hurrah! - the ordinary users have no privileges to install anything, Splash included. The only way I could implement this suggestion is by giving admin privileges to every user, installing Splash (on accounts for which I don't necessarily possess the passwords) and then revoke these privileges after. INSANE !!
I shall be uninstalling Splash now in the expectation that I will find another video player with a more sensible attitude to multiple users. I know this has become a PITA on Win7 coz M$ make it hard for installers to bend file associations. But the answer cannot be the one provided here.
PS: When I downloaded Splash from the official Download site, my AVG anti-virus PUKED BIG TIME. Some virus was apparently pulled down the pipe. I quarantined it and it evidently had nothing to do with Splash because that came down after and worked fine (-ish - see above). I am guessing that some commercial junk was prefixed that was infected. Very clever (not).