No Loops

Just bought a new iMac about a month ago and tried using Garageband for the first time on it this evening but Garageband isnt displaying any loops. I've tried deleting Garageband prefs and intsalling them from the second install disk that came with my new Mac but the installer tells me that I must have Garageband 4 or above (it is 4.0.0 - from iLife 08) and only has an option to close the intsaller !

Any ideas ?

Thanks !