For minilogin to work you must set the <address> element in the <world> section.

[Derision]

Been a while since I booted up my EQ server, but you need to uncomment the address line in your eqemu_config.xml

i.e.

change:

<!--<address>129.81.73.41</address>-->

to:

<address>129.81.73.41</address>

Assuming 129.81.73.41 is the address your world is running on.

The <world> section of my xml file (for minilogin use) is:

<world>
        <address>192.168.1.100</address>
        <loginserver>
              <host>192.168.1.100</host>
              <port>5999</port>
              <account></account>
              <password></password>
        </loginserver>

        <shortname>BTG2</shortname>
        <longname>Benden Test G2 Private</longname>
        <http port="9080" enabled="true" mimefile="mime.types" />
</world>

If I comment out/delete the <address> line, I get the same error you are seeing.