I changed the title of your post to reflect the true issue you are reporting.
What OS X version is this on?
In order to troubleshoot the error, I'll need to obtain the Flash Player install log files. Please do the following:
- Review the FAQ Where do I find the Flash Player installation log on the Macintosh?
- After reviewing the FAQ, configure your system to capture the install.log and FlashPlayerInstallManager.log files (ignore the Adobe_ADM.log and Adobe_GDE.log files).
- Once the system is configured to capture the logs, run the installer again
- When the installation fails click DONE to close the installer window
- Save the captured log files according to the instructions in the FAQ
- Upload the files to cloud.acrobat.com/send using the instructions at How to share a document
- Post the link to the uploaded files in your reply.
Was there anything written to the install.log file during the installation attempt?
What version of Flash Player, if any, is currently installed?
I am having the same problem. I can't believe there is no way to contact Adobe support directly about this! Running Firefox on OSX 10.6.8. I've tried everything.