MFC - debug assertion failed error

My MFC project was working ok. I made a change to a line of code and it then started giving me a debug assertion failed error! It points to the ASSERT ( FALSE) line of  this funtion in dlgData.cpp
HWND CDataExchange::PrepareCtrl(int nIDC)
      ASSERT(nIDC != 0);
      ASSERT(nIDC != -1); // not allowed
      HWND hWndCtrl;
   COleControlSite* pSite = NULL;
      m_pDlgWnd->GetDlgItem(nIDC, &hWndCtrl);
      if (hWndCtrl == NULL)
        // Could be a windowless OCX
        pSite = m_pDlgWnd->GetOleControlSite(nIDC);
        if (pSite == NULL)
               TRACE(traceAppMsg, 0, "Error: no data exchange control with ID 0x%04X.\n", nIDC);
      m_idLastControl = nIDC;
      m_bEditLastControl = FALSE; // not an edit item by default

   return hWndCtrl;

Does anyone know what would cause this error and what should I do to get rid of it!?

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Qlemo"Batchelor", Developer and EE Topic AdvisorCommented:
The corresonding control is not existing (anymore), maybe you renamed the resource ID. This method is called when you create (or display?) your dialog, for all controls having a member variable assigned. All such controls are enumerated in DDX_... macros.
Have a look on the resource ID in this method, and what that correspnds to.

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AndyAinscowFreelance programmer / ConsultantCommented:
What was the line of code you changed?
Qlemo"Batchelor", Developer and EE Topic AdvisorCommented:
... the most important question, this is ...
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AndyAinscowFreelance programmer / ConsultantCommented:
Look at where the ASSERT(FALSE)  line is in the code - it *could* be something completely different to what your comment suggested.
indacryptAuthor Commented:
Hi Andy...can u pls explain what you meant by "Look at where the ASSERT(FALSE)  line is in the code -"....Im not able to find that line anywhere in the code other than i nthe place pointed to b ythe debugger....
AndyAinscowFreelance programmer / ConsultantCommented:
comment meant for Qlemo.  His comment is likely to be correct but..

indacrypt - what line of code did you change?  Then we would know if Qlemo has got it right or not.
indacryptAuthor Commented:
ok i see wht you meant....i followed the IDC number from the ASSERT line and found there are two controls by that number. I have to figureout which one hass the problem now I guess. Thanks!
AndyAinscowFreelance programmer / ConsultantCommented:
I don't think the resource editor will allow two controls with the same ID on the same dialog (apart from the special IDC_STATIC that is).
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