We apologize that we cannot help you with this specific question. We have been getting technical questions like this for a while and are in the process of adding a "find a star above my address" and "find a star by astrological sign" process. This should be completed by October of 2013. If you would like to purchase another voucher or save yours until then.
Most stars can only be seen in either the Northern or Southern hemisphere. If you are in the Northern hemisphere make sure the right hand coordinates (6h 23m 57.1s, 53° 41' 44.6") are a positive number. You would need the help of a professional astronomer to interpret the coordinates to find ones directly above you.