Run the following command in terminal
sudo mv /Library/Fonts/MyriadPro-SemiboldIt.otf
This didn't help.
Have a look at the following document. It explains how to resolve Exit Code 7 error. http://helpx.adobe.com/creative-suite/kb/errors-exit-code-6-exit.html
Are you trying to install from a DVD or download?
I'm not a mac person, but do you have a case sensitive drive? I can't remember where I read about this, but in some cases it migth also cause issues. Have a look at this document as well.
I had pretty much the same error code, but a different font was named. Between the suggestion from Manish_1988 and the page linked by Vikrant Ral, I finally got my installation to work. Here's what I did:
1. Open a Terminal window and "cd /Library/Fonts"
2. Remove all of the fonts in the family that the error message is complaining about. In my case, the offending font in the error message was ACaslonPro-Regular.otf. I created a new subdir under /Library/Fonts, then moved all of the ACaslonPro* files to the new subdir. Commands were:
sudo mkdir old_fonts
sudo mv ACaslonPro* old_fonts
3. Ran the installation again and it completed without errors.
I think I was doing all of this in Safe Mode (based on the advice from http://helpx.adobe.com/creative-suite/kb/errors-exit-code-6-exit.html), but I'm not sure that was necessary. I did previously have Photoshop Elements 6 on this machine, which I believe is what put those fonts there in the first place.
Also, before I moved the fonts, I had a font called ACaslonPro-Semibold.otf.incompleteMigration, whose size was 0 bytes. Maybe this file was causing the problem, but I don't know. I think this file may have resulted from an error a couple years ago when I migrated an old MacBook to a new machine.
Hope this helps