InDesign crash while applying character style

Hi all,

A)I have problem with applying character style to selected text.

when character style is applied to selected text indesign get crashes.

my code snippet is as follow

input parameters

1.RangeData paraRange // start and end index of paragraph

2.storyUIDRef // uidref of current story

          code snippet

          // valid text model

          InterfacePtr<ITextModel> textModel(storyUIDRef, UseDefaultIID());

          if (!textModel)

   break;

          //wax strand

          InterfacePtr<IWaxStrand> waxStrand(((IWaxStrand*)textModel->QueryStrand(kFrameListBoss, IID_IWAXSTRAND)));

          if (waxStrand == nil)

   break;

          //WaxIterator

          K2::scoped_ptr<IWaxIterator> waxIterator(waxStrand->NewWaxIterator());

          if (waxIterator == nil)

    break;

          //first wax line of paragraph

          IWaxLine* waxLine = waxIterator->GetFirstWaxLine(paraRange.Start(nil));

          //iterate each waxline

          while (waxLine != nil && (waxLine->TextOrigin() < paraRange.End()))

          {

    //Iterate for all runs

   K2::scoped_ptr<IWaxRunIterator> waxRunIter( waxLine->QueryWaxRunIterator() ) ;

   IWaxRun * waxRun = waxRunIter->GetFirstRun();

   while (waxRun)

                    {

   int32 startPos  = waxRun->TextOrigin();

   int32 endPos = startPos + waxRun->GetCharCount();

   RangeData textRange(startPos ,endPos);

   ISelectionManager* selMgr = m_activeContext->GetContextSelection();

   if(!selMgr)

    break;

   //get valid textselection suite

  InterfacePtr<ITextSelectionSuite> suite(selMgr, UseDefaultIID());

                              if (!suite)

   break;

                              //select  text

  suite->SetTextSelection(storyRef, textRange, Selection::kScrollIntoView, nil);

                              //created style from selection using  " SnpManipulate::TextStyleCreateStyleFromSelection" method.

                    }

          }

my code get crashed at highlighted text( int32 startPos  = waxRun->TextOrigin();).

B)my next question is how to get textstyle ranges of a selected paragraph.

please help me.

Thanks

Tahir