I-140 request additional evidence? Pls help

Just received this message from USCIS. Could anybody explain what would happen after I receive this message? I've been waited 7 months after I ted my I-140 application.
Application Type: I140, IMMIGRANT PETITION FOR ALIEN WORKER

Current Status: We mailed you a notice requesting additional evidence.

On February 1, 2007, we mailed a notice requesting additional evidence and/or information in this case. Please follow the instructions on the notice to the evidence and/or information requested. This case will be held in suspense until we either receive the evidence or the opportunity to it expires. Once you the information and/or evidence requested, you will be notified by mail when a decision is made, or if the office needs something further from you. If you move while this case is pending, call customer service.

Any inputs are very appreciated.