Misc NDSL Crashing when connecting

[MajinGohan]

I recently got a router and a new ISP. I configured the WLAN connection on both my router and NDS, and the connection test on the handheld gives me an ok. The problem is: Whenever I try connecting to the WFC Network , my Lite "crashes", meaning the screen freezes and nothing happens.
It worked fine with my brother´s router.

I´m using a Zyxel 660HW , a router provided by the ISP called Arcor (which some German members might be familiar with).

Halp plz


EDIT: The post got cut off :/ .