DLP modules are designed to be suitable for bus-powered or self-powered use. In order to power a DLP board fro the USB port, several of the module pins must be commoned together. These are typically the VCCIO, EXTVCC, PORTVCC and RESET# pins.
For details of which pins should be commoned, please review the appropriate data sheet for the module being used. Data sheets for DLP modules are available from the DIP Modules page in the Evaluation Kits section of the FTDI website, or from DLP Design.