"Error Restoring iphone 3G -(error 1603), Please help

I tried redialling on my iphone and then it froze.So i turned it off by holding the power button.Then it didn't turn on.So i put it to recovery mode n tried to restore but during the restoring process the iphone automatically ejects after showing the apple logo("preparing to restore" step).Please help.What should i do.I updated itunes,my pc and tried dozens of times all those times it automatically ejects and itunes shows "error 1603"