I have the same problem but i know why. Limewire automatically closes after it starts up because Limewire uses the spyware called "CyDoor" which serves the ads in Limewire. If you remove Cydoors spyware using Adaware or some other prpgram, Limewire can not find the Cydoors spyware dlls so Limewire automatically closes. By the way, cydoors dlls are cd_clint.dll and cd_htm.dll which are placed in the C:\windows\system32
directory.