Problems installing reboot

I have the boxed version of SR2 and just downloaded Reboot - the first time I tried to run it it told me I needed to have SR2 installed then made me redownload but let me pick which directory SR2 was in this time. When I tried to run it upon completion of the download though, it told me a .dll was missing and began redownloading Reboot again. There's an update available for my now detected copy of SR2, but I don't have a CD key for it that I know about. What should I do? Thanks in advance.