When asking for technical help at the very least let us know the version of firmware you are running.Cliff's Calibration (Mapping) Guide is a MUST READ: http://www.vemssupport.com/forum/index.php/topic,97.0.html
You'll be hard pressed to find a new reasonably priced laptop with a RS232 connector, I know that Emil and Jorgen have newish IBMs with serial ports, but I've been using USB only laptops for about four years now.The reason I don't have any problems with the USB->RS232 converter is because I use an EasySync one http://www.easysync-ltd.com/product.php?ProductID=526The FDTI chipset seems to be one of the best.