Many times quitting your browser completely, re-opening it and going back to http://www.pandora.com can help.
If you're still having trouble with Pandora in Safari, try the following steps:
1. Update Safari: http://www.apple.com/safari/download/
2. Clear your browser's cache and history. In the Safari menu, select Reset Safari. Then restart the browser and go back to http://www.pandora.com
3. Install the latest version of the Flash player using the appropriate link for your operating system:
http://get.adobe.com/flashplayer/
(If you have an older Mac with the PowerPC processor, the highest version you can run is 10.1.102.64--See here for archived versions: http://forums.adobe.com/thread/843750)
4. Make sure to bypass your Pop-up Blocker for Pandora:
(If you have an older Mac with the PowerPC processor, the highest version you can run is 10.1.102.64--See here for archived versions: http://forums.adobe.com/thread/843750)
4. Make sure to bypass your Pop-up Blocker for Pandora:
Select Safari -» Preferences -» Security Tab. Under "Web Content", check every option except for "Block pop ups". Also, make sure you don't have the browser set for "private browsing" in the Safari menu.
5. If you have the AdBlock extension, rightclick on Pandora and select 'Don't run on this domain' and then click Exclude. Also, make Pandora an exception if you have the ClicktoFlash or ClicktoPlugin extensions
6. OS X 10.7 doesn't always play well with Adobe Flash, you might try this: Open System Preferences -> Energy Saver and uncheck "Automatic Graphics Switching
8. Finally, if your issue persists, restart your computer and go back to http://www.pandora.com