Because Apple changed the AFP version from v1 to v2, there are no connections possible through AFP from Mac to OES2 Linux nor NetWare... Solution: 1.Open up a Terminal on your Mac and make /Library/Preferences writable:
sudo chmod o+w /Library/Preferences
2.Switch back your Lion to AFP v1:
sudo defaults write /Library/Preferences/com.apple.AppleShareClient afphostprefs_version -int 15
3.Reboot your Mac !! (this is necessary just one time)
4.Try to connect to your Server again. It may still fail.
5.Open up a Terminal again and type:
sudo defaults write /Library/Preferences/com.apple.AppleShareClient afpdisableduams -array "Cleartxt Passwrd" "MS2.0"
6.Now the AFP connections should work...
7.Change back rights to /Library/Preferences/ with:
sudo chmod o-w /Library/Preferences