SilkTest 2008, V 9.1.0.2085 from 2008-06-17

We use SilkTest for Testing a RichClient GUI (WinApplication based on a Visibroker Framework).
The silktest function pick does not work well after a hardware change (from a Pentium 4, 3 GHz, 1.9 Gbyte RAM to a 1.99 GHz and 3.43 RAM machine).

What is the problem:
The silkscript runs well on the old hardware.
The silkscript runs well on the new hardware in the debug mode (F8).
The silkscript does not run on the new hardware in the debug mode (F9)
The silkscript does not run on the new hardware in the run mode.

What is the action, that causes the problem:
<window>.<Menu item>.<element #1>.Pick ()

workarround:
The menu element can be addressed by a shortcut
<window>.TypeKeys ("<Ctrl-Shift-b>")

That way the regressiontesting can be continued but the problem is not solved.
Does anybody know the reason for this behavior?