Acrobat X Pro crashes when document closed if launched from COM API

Question

Environment: Windows 7
Acrobat X Pro
I'm seeing some unusual behaviour when running the following code which simply launches the Acrobat Application and opens up a document with Acrobat X Pro.  Closing the document causes the program to become unresponsive and then crash.  The crash dump shows the exception as "The thread tried to read from or write to a virtual address for which it does not have the appropriate access".
I've discounted a problem with the plugin I wrote since the program also crashes without the plugin loaded. 
Same code runs fine with Acrobat 9 using the version 9 acrobat.tlb.
Can anyone help or advise?
With thanks,
Evan
HRESULT hr = E_FAIL;
VARIANT_BOOL bRet;
  try
::CoInitialize(0);
CComPtr<Adobe10::Acrobat::CAcroApp> pApp;
CComPtr<Adobe10::Acrobat::CAcroPDDoc> pDoc;
CComPtr<Adobe10::Acrobat::CAcroAVDoc> pAVDoc;
CComPtr<IDispatch> pDisp;
CComPtr<IUnknown> pUnk;
CComPtr<IUnknown> pUnk_App;
  if (SUCCEEDED(hr = ::CoCreateInstance(__uuidof(Adobe10::Acrobat::AcroApp), 0, CLSCTX_ALL, IID_IUnknown, (void**)&pUnk_App))){
hr = OleRun(pUnk_App);
if (SUCCEEDED(hr)){
hr = pUnk_App->QueryInterface(&pApp);
if (SUCCEEDED(hr)){
pApp->Show(&bRet);
else
  return hr;}
if (SUCCEEDED(hr = ::CoCreateInstance(__uuidof(Adobe10::Acrobat::AcroPDDoc), 0, CLSCTX_ALL, IID_IUnknown, (void**)&pUnk))){
hr = OleRun(pUnk);
if (SUCCEEDED(hr)){
hr = pUnk->QueryInterface(&pDoc);
if (SUCCEEDED(hr)){
hr = pDoc->Open((BSTR)CComBSTR(strPath), &bRet);
if (bReadOnly == VARIANT_TRUE){
pDoc->SetInfo((BSTR)CComBSTR( 
"ReadOnly"), (BSTR)CComBSTR("yes"), &bRet);}
hr = pDoc->OpenAVDoc((BSTR)CComBSTR(strPath), &pDisp);
if (SUCCEEDED(hr)){
HWND hwnd= ::FindWindowW(_T( 
"AcrobatSDIWindow"), NULL);  
if (hwnd)ForceForegroundWindow(hwnd);
catch(const std::wstring& s){
EC_TRACE(LVL_ERROR, s.c_str());
if (hr == S_OK)hr = E_FAIL;
return hr;

Answer 1

Problem solved. Evidently, the lead document in the file was corrupt. I recreated the file and it compressed without any problems.