Make sure the Mix Knob on the 22VSL is not turned all the way to the right.
The Mixer knob allows you to blend your input signals with the playback streams from your computer. This allows you to monitor your input signal with zero latency. If the knob is positioned at 12 o’clock, the input signal and the playback stream will be equally balanced. Turning the knob to the left will increase the level of the input signal relative to the playback stream; turning to the right will increase the level of the playback stream relative to the input signal.
If you're still having trouble open a support ticket with us at http://support.presonus.com
so we can help you as the problem may be deeper than just this.