delete *CXTPCommandBars -> compiler error

Hi,

I am using "Xtreme Toolkit Professional Edition v9.51 MFC for Visual C++".
At "delete m_pCommandBars;" in OnDestroy i get the compiler error "C2248: ... no access on protected element ..."

Any ideas? Here is a snippet of the code i am using:
class CDlgPreview : public CXTPDialog
{
private:
 CXTPCommandBars *m_pCommandBars;
... 
}

BOOL CDlgPreview::OnInitDialog()
{
 CDialog::OnInitDialog();

 m_pCommandBars = CXTPCommandBars::CreateCommandBars();
 ...
}

void CDlgPreview::OnDestroy()
{
 CDialog::OnDestroy();
 delete m_pCommandBars; // --> error C2248
}

Thanks for your help.