Hi welcome to the forums
first of all dont use WEP, WEP is so weak as a security key i would never recommend it, WPA - AES is the safest and most secure option.
You need to find out what type of network key encryption is on your network, you can find this in your router, The same type of encryption on your router must match the device , WPA - WPA you cant have WPA2 - WEP, it wont work
check you settings on your network and let me no, GOOD LUCK