I downloaded 911: First Responders from Amazon.com. The game plays fine as does the LA Mod. However, I cannot install any other mods because when I try to run ModInstaller.exe I receive an error that 911:First Responders is not properly installed. Please Reinstall. I've searched the forums and attempted this fix. The differences would be WizardWorks instead of Sixteen Tons Entertainment and 911 - First Responders instead of Emergency 4 US. No variation I tried allowed the ModInstaller