Hmm -- If you can, try going to Tools -> Options, iTunes -> Sharing, and uncheck 'Share My Music'.

If LimeWire crashes before you can get to that point, locate a file called "limewire.props" on your computer. It should be under C:\Documents And Settings\<yourusername>\.limewire\limewire.props. Edit that file to have a new line that reads:
DAAP_ENABLED=false

then save the file and start LimeWire. (Make sure LimeWire is closed while you're editing that file.)