itunes crashes airport extreme wifi with remote disk

This has been happening for a while. I have an Airport Extreme with a USB drive attached, which has two machines backing up to it and my itunes library. When I open itunes on a wifi attached machine it accesses the remote library no problem. If I have my iphone attached to sync or if I update apps in itunes the Airport crashes, wifi is disconnected and I get errors about not being able to update the library etc. I've tried making sure no other machines are accessing the disk at the same time.