foxey im having a heck of a time with thte same thing so i can't tell you much but i do recomend using webmin to configure your samba server, i know it's on the mdk 10.2 disks.

question if i may. im at home vpn'ed in with a 192.168.56.0/24 address. the AD server is on a 10.0.0.0/16. would this be the reason why a can't join the domain? this doesn't preesent a problem for windows machines.
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[root@localhost samba]# net rpc join member -U <domain\admin>

Unable to find a suitable server
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