cs4 is an earlier, not later version than cs5.5
assuming that was a typo and you really want to install cs4, uninstall cs5.5, restart your computer and use the adobe cleaner: http://helpx.adobe.com/creative-suite/kb/cs5-cleaner-tool-installation-problems.html
then install cs4.
Oh yes that was a typo. I uninstalled and used the cleaner tool but I still get the same message when trying to install CS4. I tried again and restarted my computer. The same system error shows up telling me to switch or retry. I clicked retry. It acted like it was going to try but then I get an error message.