No. Registering your songs with RouteNote does not inhibit your ability to get signed to a label. RouteNote will never prevent you from doing anything you want with your music.

For YOUR sake, please note: If you sign two digital distribution deals with two companies that will both be sending the same album to iTunes, Rhapsody, eMusic, Limewire, etc. - this will hurt you, because the retailer will usually remove the album completely until you decide which distributor has the exclusive right to be selling that album through them.