Adobe Reader 6.0 Installation - French

Hello, I can't finalize the installation of Adobe Photoshop and Adobe Illustrator. I'm working with Windows XP Pack 2. I get the following message: "The installer has detected that a more reliable product is already installed. The installer will now close." Corel Draw and Corel Photopaint are already installed on my computer. I get the same message even with the antivirus disabled. The Adobe plugins on the internet are enabled. What should I do??

Configuration: Windows XP Internet Explorer 7.0