Thanks, I will test xterm as you suggest. In the meanwhile, I welcome anyUnfortunately I don't have much to add Towhid. I'm using Kubuntu 9.04 with tn5250 out of the repositories - but I don't have any problems. The warning messages telling you that "black" and "white" are not defined makes me think something is missing from your OS... when you installed tn5250 (or xterm) were there any errors?
insights from all Ubuntu users. Thanks.