PQL II: picking problem

I have installed PQLII on a 64-bit linux pc having UBUNTU 10.010 as operative system. The software works but not in all its functional features. I have problem with picking and with the traces sorting. When I work in "Magnify" mode and I pick SAC traces, the picks do not remain fixed to the corresponding trace. The marker of picked time change their positions when I make a different zoom on the trace. If I save the picks in a file I observe two different marker, the first is fixed to the picked time whilst the second one changes its position following the zoom window. This problem makes not practical the picking task. I encounter another minor problem when I try to sort the traces. I cannot sort the traces using some variables into the header of sac traces like station LAT, station LON. Thanks for your help.