Memory Access Exceptions

When I call some VixCOM apis I get a memory access exception when it's called.

Specifically the FileExistsInGuest API is called when I call it:

_virtualMachine.FileExistsInGuest("C:\Windows\Notepad.exe", null);

this throws an AccessViolationException.

Is this function not supported in VMWare server 1.0?

If not, is there a note as to what APIs are not supported by VMWare server 1.0?

This was the same exception I got with the FindItems API I believe.