Can't listen to audio podcasts from internet radio

Are you certain you have deleted ALL of MacKeeper?

Some things to check:

http://applehelpwriter.com/2011/09/21/how-to-uninstall-mackeeper-malware/

https://discussions.apple.com/docs/DOC-3036

(Please note that references to the original developers, Zeobit, should now refer to Kromtech Alliance Corp, who acquired MacKeeper and PCKeeper from ZeoBit LLC in early 2013.

If after you go thru all these steps; Then uninstall Flash:

http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html

Then reinstall the latest version 11.9.900.170 select your OSX from the installer, set Safari preferences "Save downloaded files to:" select desk top, in the drop down select other, then select desktop from the left column, this will put the stand alone installer on your desk top, open it and follow the prompts, close all applications prior to starting the install. When the install has completed, click done, quit (if necessary) and log out, reboot and log back in.

in iTunes menu bar click Files>Subscribe to podcast and make sure that the URL is coorect, or possibly semove and reinstall the URL. (Seeing as you have youtube, etc, that was not the issue)

Also maybe some help here:

http://support.apple.com/kb/HT1747

Try a safe start, thus can some times fix small glitches.

Power up holding the SHIFT key, continue to hold till you see the progress Bar, then release and allow to finish booting. (Note that this will take longer than a normal boot, be patient.)

In your login screnn it should say in red font SAFE MODE.

This will disable some softare, (especially 3rd party)

Try checking thru and see what you get. Log out and reboot normally and try it out.

Also maybe some help here:

http://support.apple.com/kb/PH12267

Maybe thes folks can point you in the right diection:

http://www.apple.com/support/itunes/contact/

Hope something helps