SetWindowPos causing crash

Hello again experts! Thank you for reading this post.

Anyone ever heard of SetWindowPos causing an application to crash? Even
more so causing a severe error that a try catch(...) was unable to catch?

More details:
--- In ParentWindow.h ---
CTestWindow * dlg;

--- In ParentWindow.cpp ---
dlg = new CTestWindow();
....
dlg->Create(CTestWindow::IDD); // crashes here sometimes (see below for
init for this window)

try
{
   dlg->ShowWindow(SW_SHOW); // also sometimes errors out here
}
catch(...)
{
    // logs error
}

--- In TestWindow.cpp in OnInitDialog() ---
....
try
{
        SetWindowPos(NULL, windowPositionX, windowPositionY, 50, 50, SWP_NOSIZE |
SWP_NOZORDER); // crashes whole program here (windowPositionX and Y are
always positive legal values as I log them before this executes)
}
catch(...)
{
// logs error.. well, it is supposed to but the try-catch will never log it
since the program crashes
}

Who knows... maybe this is not where the problem is, but I am logging lines
before and after each and every line in the parent and child window and this
is where is consistently stops. Spent over a day now looking at this.

Another note: This error usually happens after about 40 successful cycles
of the code.

Any thoughts?

Thanks,

Rob