this has been discussed many times before

is the rule of thumb in this one, BUT, to summarise -
UNINSTALL ALL of the existing software for the lilli. ALL of it, even registry entries.
Disconnect the Lilliput from the PC.
Install the drivers WITHOUT THE SCREEN ATTACHED TO THE PC
then, install the lilliput, and it will be detected like plug n play, AND will find the drivers you installed...
then, its supposed to work...