Ok, i've tested this simple level at another PC with another graphic adaptor (a SIS graphic card) and the release version of DirectX and WinXP(SP1). But the problem is still the same even with that very simple test level. if you turn off the second view, it's ok, if it's turned on, the main camera is clipped as well.
Maybe that problem is only with the PRO version? I think not too much have the pro version so maybe that's why it does not show up on every system?