The following should all be done if your having problems connecting online with COD4.

*Ensure UPnP is turned off in your PS3. (This is under network settings. It can be ON in the router.)
*Ensure you NAT type is 1 or 2.
If using a router your NAT type is 2. If plugged directly into your modem your NAT type is 1.
With NAT type 3, it may not be possible to communicate with other PS3™ systems, and voice / video chat are restricted.
(If your NAT type is 3 see below.)

Ensure the following ports are open on your router or firewall.
TCP: 80, 443, 3074, 5223
UDP: 3658, 3478, 3074, 3075

(Note: These ports need to be mapped to the IP address of your PS3 in your router.)
You should be golden now!


NAT type 3 Problem, Fixes
The port numbers for PLAYSTATION®Network servers are:
TCP: 80, 443, 5223
UDP: 3478, 3479, 3658
Ensure UPnP is turned off in your PS3.

Any further questions or anything feel free to ask.

luckily i dont have these problems

I occasionally get the downloading game settings problem when choosing the "find game" part. to fix it i usually just turn off my router and turn it back on again. Next time il try doing this instead.