Hi, Problem was solved when i was posting this reply... I didn't checked most obvious thing - drivers version, when i asked IT for update, everything started to work just fine.
For future seekers here is reply to upper questions: 1 - On windows XP there were no problem at all. 2 - I have only one Visilogic PLC for my disposal (SM35 mentioned earlier). 3 - Dell PR12s docking station equiped with LadderComOp2 (Drivers 2.0.0.0) No-Name,as well as Automation Direct GoldX, Profilic USB-to-Serial Comm Port (Drivers 3.3.2.102) Working setup: GoldX converter and 3.4.67.325 drivers. Thank You for reply!