Xiaobaitu & pigpig: pls help!

I filed my I-485 in 09/2005 and got married in 2006, my wife joined me last year. I filed my wife's I485 documents before my PD (07/2006) is availble,and today I received an email from USCIS.

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

On May 7, 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.
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BUT the paper check was not checked out.

Could you tell me what is going on? Did USCIS receive or reject her petition? Thank you!