After upgraded my WL-500g with the customized firmware (both 1.6.5.3-3 and 1.6.5.3-4), some web-addresses became inaccessible. The two addresses I so far got problem with is:
www.adressa.no
www.nokiausa.com

Tried to reintall firmware, reset the router, turn it off and on and so on without any success. Finally I had to "downgrade" my firmware back to the originally 1.6.5.3 from ASUS and then there is no problem to access these addresses.

Any suggestion?