Received this reply from the site:
Thank you for emailing us regarding this issue. Currently we are aware that that there are problems with playing WMA streams on Mac OSX 10.6 and 10.7, across all browser types depending on your particular setup. We are continuing to investigate this issue. In the meantime, if you go to the station page and scroll down a quarter of the page on the right-hand side under "Internet Listening" you will find the different streams for the station. You should be able to play any streams that do not have the Windows logo (four squares).
If the station you'd like to listen to only has a WMA stream, please see the possible workaround below. We apologize for the inconvenience and thank you for using TuneIn!
Workaround:
1. Click Listen.
2. TuneIn's Pop Up Window will open
3. Copy Address in the Pop-Up Window.
Example:
http://www.tunein.com/tuner/?StationID=24889&4. Paste into a new browser window address bar.
After the "&" type debug=1 and hit enter.
Example:
http://www.tunein.com/tuner/?StationID=24889&debug=15. The stream will open.
Please let us know if you continue to experience issues.
Sincerely,
Kyle
TuneIn