Your fix might work, but I have no idea how to implement it.
1. What "optimized client" are you talking about? Form where can it be downloaded? How does one "expand" it?
2. Copy all of what files? What/ where is the "zip file"?
3. How does one "reinstall the boincmanager"? Who "repair(s) permissions" and "on" what folder?
And I am not interested if spending half a day figuring it out.

1:Click this link to be taken to the post on this forum that has links to the optimized apps.

http://setiathome.berkeley.edu/forum_thread.php?id=31810&nowrap=true#656269

2:The Mac has built in tools to unzip the archives.

3:The easiest way I have found is to shut down the boincmanager, then download the optimized client for your processor and expand it.

Go into your hard drive/Library/Application Support/Boinc Data/Projects/setiathome.berkeley.edu folder and copy in all the files from the zip file.

Boincmanager download if you do not have it on the hard drive of your computer.

Next step is to reinstall the boincmanager to repair permissions on the folder. It should take about 30 seconds.

It should start up and start crunching with the optimized worker.