I have Premiere Elements 9 and have been having great difficulty getting it installed since my purchase almost one year ago. I purchased the Photoshop Elements / Premiere Elements 9 combo. Photoshop Elements 9 installed without incident. After many attempts over the many months, today I was successfull. After reading all the online and Adobe.com help discussions, I noticed one discussion that mention deleting a font from the Library/Font folder. I deleted one font MyriadWebPro-Italic.ttf, which was recommended on a discussion thread. I attempted to install again with no luck. I noticed in the error message received after each failed install that another font was listed. It was an .otf font but I can't remember the file name. I deleted this file as well. I also copied all the Adobe Premiere Elements 9 folders from the DVD to my hard drive. I then attempted to install Premiere Elements 9 again and to my pleasant surprise it worked just fine.
My advice is to copy all the Adobe Premiere Elements install folders/files from the DVD to your hard drive and install from there. If nothing else it is faster this way. Pay particular attention to errors regarding fonts. Delete the mentioned fonts from the Library/Fonts folder and then install.
I would like to add that I originally was unsuccessful installing PRE9 using OS 10.6. I had installed OS 10.7 when it became available. I had contacted Adobe Tech Support once about a week ago and was unsuccessful following the advice given, including uninstalling Adobe Photoshop CS4 from my iMac and installing from the System Adminstrator log in. Either the fonts were the issue or installing from my hard drive not the dvd was the issue.
I hope this helps someone get up and running with PRE and avoid some aggravation.