Why do the outside of my feet hurt when I rollerblade?

I'm wanting to start playing ice hockey so I bought some roller blades so that I can practice at home (since skating and roller blading are virtually the same). They are of a very good spec (made by Bauer) but I can't skate for much more than five minutes before the outsides of my feet start to hurt really badly. I've tried loosening and tightening the laces to no effect - tightening makes it hurt faster. Any suggestions? From people who have actually experienced this please no time wasters.