I understand that you do have Vanilla RTW patched to 1.5, and are now sick and tired of having to point an installer to it over and over again?
I also understand that you downloaded EB 0.8, without any trouble (perhaps your download was interupted, perhaps you used a link which is not officially supported... describe it all. My download is 363.065 kb in size, thus, should a quick check on your part lead to a different size...> probably corrupted/wrong download link.)
I got it that you hadn't any trouble at all during the EB installation process (you double clicked the installer, ran it, and didn't do anything but specify what your Vanilla RTW 1.5 folder actually was, it did it's work and gave the sweet 'installation succes' message)?
I got it also that the installer made a shortcut on your desktop, which has the correct path (adress) and the -mod switch in the target line?