If you are running Windows 7 64 bit you will have to use DF1 driver for a UIC
When you load RSLinx on the PC and if its a 64 bit machine RSLinx will not install all the drivers, only the one that are compatible with a 64 bit system
See attached screen shot for using DF1 driver and the UIC, this can be used for all systems if needed as RSlinx 6.3 and earlier did not have 'UIC devices' driver