You need to obtain your gateway address from your computer.
You can go to the start tab on your desktop, go to run and type in CMD, this will bring up a command box; in the command box type in IPCONFIG, this will show your current ip settings and the gateway address will be visible. You need to insert the gateway address into your browser address bar, this will bring up the admin console applet box asking for credentials to your router. If you have not set the admin password XXXXX Username: admin, Password: admin, admin, 1234 respectfully.
Once inside the router console you can search for ICMP in the wireless settings. You will need to make sure it is not enabled.
Once done you need to do a factory reset on the roku.
Factory Reset for Roku Instructions
1. From the Home screen, press Up the Menu Bar.
2. Select Settings.
3. Select Factory Reset.
4. Select Factory Reset again.
5. Select Yes.
Additionally, you can press and hold the Reset button on the back of the unit for 15 seconds.