You might have to. You should only have one client installed into the RO folder >.> reinstall KRO and Sak into a clean folder on the desktop or something, then update them. then install the HeRO client into that folder and then you should be able to play.
if you get that error again after this then it meens that your download of kro and sak was either corrupt, or wont update, and you'll have to redownload them.