Mac OS X 10.5.8 gets wrong IP address from wireless router

The IP address 169.254.59.233 is not being provided by your router but is being created by your computer in an attempt to communicate with your router's DHCP server - and failing. You should check the wireless connection to make sure it's actually attaching to the network and the authentication details are correct.

The routers are not the problem. The problem is your Mac. Run a software update. Since you say this issue occurs only sometimes, this leads me to believe its not your network settings (which should take effect all the time).

Most likely you need a driver update. If all your drivers are up to date and the problem continues I suggest you try a reformat. If it still doesn't work replace the wireless network card.

Please check the list of preferred networks and delete network names you do not use. To do this, open System Preferences... >>Network Select your Airport name, click Advanced... at bottom right, use the '-' to delete unneeded preferred networks.