embassy sent to me my visa and i noticed iv issue date 23dec2012 and iv expires on 01oct2012 what it mean

You state that your IV (immigrant visa) issue date was December 23, 2012 and that the visa expires on October 1, 2012. I suggest that you or your representative contact the Embassy and request correction of the immigrant visa. An immigrant visa when issued is to have 6 months validity from the date of issuance. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.

That sounds like a typographical error.  You may be able to resolve it at the border, or you can go back to the consulate the resolve it.