Security reasons?
 

I keep receiving the message "LimeWire will not launch the specified file for security reasons." Why am I getting this?

If you try lauching a file that has a .exe extension (for example) then LW will indeed not launch it 'cause it may contain a virus (.exe files are the most dangerous ones. Avoid dlding them). If you still want the file then wait till the dld is complete, then scan it with an Antivirus and then open it.