I’m just going to ask, I had the exact same problem with the exact same message, but what it ended up for me was that my uninstall for the previous release failed. Once I ran the uninstall again the install worked the second time. Did you try uninstalling it agian. The reason I realized my old version was still there is that the old navigator icons still worked.
One additional thing: make sure you follow the instructions:
"We would recommend that you uninstall previous Beta build(s) before install build 1042.
If you have the previous Beta build 1014 or 1028 installed, please uninstall the application running Quest Installer from Start->All Programs->Quest Software->Quest Installer->Quest Installer. Please do not uninstall using the Control Panel. "
Message was edited by: Lozier