What version of OS X is installed on your iMac?
If you check the Minimum System Requirements you may see that your OS version does not meet the minimum system requirements to run the software.
Ok, you seem to be meeting most of the system requirements so far, so the only other one I can think of is that your iMac must be a 64bit system to run the Avid software.
To check if you are running the 32-bit or 64-bit kernel, launch System Profiler and click on the "Software" heading in the Contents section.
The line "64-bit Kernel and Extensions" will say "Yes" if you are running the 64-bit kernel and "No" if you are running the 32-bit kernel....
Ok, I will return this question to the question list to see if the other experts have any further idea on the problem.
Thanks for the update.
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I am a user of this site just like you, so I cannot see any account or refund information.However, I do know that I have not been paid anything for my time on this question page, and any money you have paid to the site is still in your JustAnswer account for future questions.Let me know if I can help with anything else on your iMac,Best,Pete.