I've done that in the past - nearly bricked the little bugger. I'm not courageous enough to try that again - plus it looks like an updated installer as well (the older ones all had the same name/file size, and this one is quite different.)
I would recommend people to not mix/match the installer with the firmware files...Mr.Hisound himself sent me a PM the last time I did that telling me it was not a bright idea
But didn't you use a completely different firmware with the installer (one meant for the original Studio)? My point is the installer is just the installer. The firmware itself is what is being actually installed and has any bearing on the player itself. Not the installer so much. What I'm saying though is this is most likely that new firmware that I tried out. I had the same issues with the installer being corrupt. I had to use the one from my previous firmware to get it to install. I still didn't like how it functioned so I reverted. I don't think it is worth using. Although there are some perks like the unit will remember more of your settings upon resetting. That's about it for me in the positive.