Are you relatively new to selling on Ebay? Jeff is quite right, Ebay has restrictions on what they consider to be high risk fraud items. The 1 and 3 day auctions are favored by scammers so they keep a close eye on those.
If you're a more established seller there shouldnt be any problem, but for the time being, try 5 or 7 days. They probably won't let you list 15 of these items either if you're new, usually they put a limit on that too.
Sorry, not really much you can do..