Have you seen this?
Yes, I also agree with Harbs's suggestion because this extension works fine on windows. If you are using Extension Manager CS5, make sure you have patch5.0.3( http://download.macromedia.com/pub/dw_exchange/extension_manager/mac/A dobeExtensionManager_5_0_3_mul_AdobeUpdate.dmg ) installed. If you are using Extension Manager CS5.5, make sure you have patch5.5.3( http://download.macromedia.com/pub/dw_exchange/extension_manager/mac/A dobeExtensionManager_5_5_3_mul_AdobeUpdate.dmg ) installed.
If you are using Mac OS X 10.7, please update Extension Manager to 5.0.2 then reinstall this extension. You can update Extension Manager via Adobe Application Manager or manually downloading and running http://download.macromedia.com/pub/dw_exchange/extension_manager/mac/A dobeExtensionManager_5_0_2_mul_AdobeUpdate.dmg. If it still doesn't work, please send it to my mailbox. I cannot access the download link you gave me. I got 404 error - File or directory not found. Please see private message for my mailbox.
The signature validation issue was solved by 5.0.2 patch. The 5.0.3 patch was intended to solve importing InDesign pre-installed extension issue on Mac 10.8, this patch will not be listed in Adobe Application Manager window if you are running Mac 10.7. As a result, Automatic update to 5.0.3 is unavailable for Mac 10.7 users.