Do you have the limewire player on ???
Go to tools > options > player and check the box and select apply...
Alternatley you dont have to use this player as it can be unreliable...
You can use WMP or itunes and so on...
To use one of these players go to your shared folder outside of limewire and right click on the file
Go to open with
choose your player
select the box that says always open these file types with this program...
That way you have selected a default player....
BTW you will have to download a player if you do not have one...