>>53393no, you should never have to pre-wear your brake shoes. loosen your cable tension; it might be as simple as "tightening" your barrel adjuster, or as "complex" as just re-adjusting the cable tension itself using an allen key
there also is the slight possibility that you purchased incorrect brake shoes--if you ride campy, make sure its campy compatible, if you ride shimano (or generic) make sure its shimano compatible, etc
you also might want to get brake shoes that have replaceable rubber; in the long run you'll save a few bucks