taxes are important for citizenship as they may be evidence of your "character". You should certainly seek assistance from a qualified tax adviser if you believe your taxes are accurately filed (in the way of a signed letter from a tax adviser confirming this). Also, you should seek assistance from an immigration attorney to handle the issue.
P.S. See my recent blog post on this very topic: www.swagatusa.com/blog
Did you fail to file required taxes? Did you lie to USCIS? This is why they are requesting this info, but it is hard to speculate. I would hire a lawyer as USCIs is digging into your case
For more immigration information, please visit www.immigrate2usa.com
Neil I Fleischer (513) 977-4209 www.immigrate2usa.com Note: Neil Fleischer is an attorney licensed in the State of Ohio The below answer is provided for informational use only. One should not act or refrain to act solely based on the information provided. No attorney/client relationship is created unless an Agreement is signed by the attorney and the client. Best regards, Neil Neil I Fleischer The Fleischer Law Firm, LLC 917 Main Street Cincinnati, Ohio 45202-1314 Direct telephone: 513 977 4209 firstname.lastname@example.org Enjoy our Blog at http://immigrate2usa.blogspot.com/