Error during setup

I just got my Time Capsule today an tried to set it up. I installed AirPort on my computer, followed all the directions to connect the Time Capsule to the internet and power source. AirPort was able to see the wireless device and I clicked "continue" to set it up as an AirPort Base Station. Next a window pops up that says "detecting Apple wireless devices. Please wait..." I wait about a minute and then I get an error message: "An error occurred while trying to access the Apple wireless device. Make sure your network connection is valid and try again. Error -4" I'm not sure what to do about this. I tried unplugging the Time Capsule. I've rescanned for it and tried the setup again. I installed AirPort on our other laptop and tried configuring it from that computer. I always get the same message. I'd appreciate any help--thanks.