hi i had the same problem i tryed everything then after readin loads i went here and downloaded this driver works perfectly now.
the driver that comes with the lead uses normall windows buffers you need to update these from here LATEST FTDI CDM Drivers 2.06.00 http://www.ftdichip.com/FTDrivers.htm
THATS IF YOUR LEAD HAD THIS CHIP INSIDE IT MOST HAVE.
check my other posts m8.
It worked straightaway on my 2002 1.6 Stilo and I was able to read fault codes and run all engine parameters and graphs. Superb software. Well done Yani!
Nice to be able to save the data to a csv file and view later in Excel too
Excellent job!