I always had a suspicion the 'cannot scan file for virus' problem and the iTunes transfer problem were related to each other.
You can usually access your preferences folder easily via typing
%appdata%\LimeWire either into the Run utility or for Windows 7, the search box in the Start menu.
You could even paste in
%appdata%\LimeWire\limewire.props
to find and open the document.
I opened the limewire.props file using WordPad so it retains its formatting and easy to add or replace lines of text. Saved as standard text making sure the .props file extension was retained.
BTW only the 5.5 Pro versions had the disable AV Scan files after download option. LPE does not have this option.
sample 1, finding limewire.props file on Windows 7 . . . sample 2, finding limewire.props file on Windows 7