For testing purposes, please try connecting in an unsecure mode.
If the connection is successful try using WPA-AES security only, try to avoid TKIP or a combination of WPA-AES+TKIP .
If the issues persist, check if there’s a firmware update for your router.
The fact that your ThinkPad successfully connect to another networks eliminated the possibility of a bad integration of the wireless card.
Setting the router to WPA-AES only seemed to do the trick.