Not sure if you've sorted this by I've been having the same problems. It seems that one of the versions of macromedia flash deletes a file called wavemapper from the windows registry; I understand that this manages all your internet sounds.
All you need to do is to open registry editor by going to Start menu, Run, type regedit and then Enter. After that, in the registry editor, walk yourself through the tree in the left hand pane, untill you reach
My Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32
Then on the right pane, right click and click on New, select String value, enter "wavemapper" (without quotes of course), ENTER, then right click on the new file "wavemapper", press modify and type "msacm32.drv" in the box that says value data and press enter.
No need to reboot, it should work straight away.
I got this information from the adobe forum. There seems to be loads of different solutions but the one above worked for me.
http://www.adobe.com/cfusion/webfor...id=184&threadid=1252570&enterthread=y#4517539