This worked for me: I have a internal audio chipset, some Realtek thingy. This ones sample rate was set to 48000Hz,24 Bit. I just set my UX2 to the same sample rate, 48000Hz, 16 bit, and this worked.
For all, who dont know how to achieve such: Right Click on the small speaker symbol in the Task bar at the right. Then choose "Playback Devices". Then choose your Line 6 UX 2 device, right-click and select properties. In on of the tabs (the last i think it was), just select the sample rate needed.
Repeat the same process, but for your recording device! Hope this helps!