After I tried "lubuntu" instead of 'lxde" as desktop manager, all worked like expected.
Then I tried it from pcmanfm within 'xfce', 'ubuntu', which failed too. Starting via "Tools"-->"Run a Command in Current Folder..." worked always.
After I tried "lubuntu" instead of 'lxde" as desktop manager, all worked like expected.
Then I tried it from pcmanfm within 'xfce', 'ubuntu', which failed too. Starting via "Tools"-->"Run a Command in Current Folder..." worked always.