I fell over this thread when I was installing a 10.4 in a VM today.
I had some other problems (network configuration), but when they were solved the XDMCP issue turned up.
It took about 5 mins to solve that problem!!! In my /etc/gdm I have an xml schema called: gdm.schema. In the schema you will find a key called: enable/XDMCP. It is a boolan value and it was set to false. I changed it to true and rebooted my system. I'm now happily connecting to the server with Xming using XDMCP.
I fell over this thread when I was installing a 10.4 in a VM today.
I had some other problems (network configuration), but when they were solved the XDMCP issue turned up.
It took about 5 mins to solve that problem!!! In my /etc/gdm I have an xml schema called: gdm.schema. In the schema you will find a key called: enable/XDMCP. It is a boolan value and it was set to false. I changed it to true and rebooted my system. I'm now happily connecting to the server with Xming using XDMCP.