Mozilla tells me: "The proxy server you have configured could not be found. Please check your proxy settings and try again."

This is the output of my proxy server (IP: 169.254.113.73)
>desproxy-socksserver.exe my.proxy.server 80 10080
>-----------------------------------
>desproxy-socksserver     0.1.0-pre3
>
>(C) 2003 Miguelanxo Otero Salgueiro
>-----------------------------------
>
>TCP port 10080 Bound & Listening
>Press <Control+C> to Quit

On another computer (connected via a 2nd network card) in Mozilla I choosed manual proxy configuration and entered:
SOCKS Host: 169.254.113.73
Port: 10080

What is wrong with my proxy settings?