It's probably the crappy limewire player it's not very reliable...
I would suggest you use a third party player like itunes or WMP...
To make one of those players your default player click on one of your files in your LW library and click on explore, your shared folder will appear,
now right click on one of your MP3 files
Select open with
Select choose program
select the player you want
and tick the box that says always use this program to open this file type
Select OK
Make sure you disable the LW player go to Tools > Options > Player...
