You will likely get this error if both devices are trying to assign themselves the same internal IP address. For example, if two devices are using 192.168.1.2 this will create the conflict.

You need to make sure both the PS3 and the computer are both using DHCP and not manually assigning the same IP's.

How to Obtain IP Address and DNS server address automatically under Windows Vista:

Go to:

Control Panel -> Network and Sharing Center

Click "Manage Network Connections"

Find Local Area Connection, double click, go to Properties:

Double click Internet Protocol Version 4 (TCP/IPv4)

"Obtain an IP address automatically"

"Obtain DNS server address automaticaly"