Dude, you're doing something wrong somewhere. The DNS error of the Ps3 has nothing to do with you not being able to login into your router. You must have had entered wrong values in the Ps3's settings, like a wrong gateway and such.
Try this guide instead, it's the best I know.
oh aak BTW i live in sweden, saw that you asked but it didn't reply
Enter 220.127.116.11 & 18.104.22.168 as the DNS' values.