Execute MSI from an .exe

Hi all!

I am calling a MSI from an EXE using MFC dialog application. I am
working on Windows-XP(SP2) using, IDE is Visual Studio 6.0.

If same version of product has found on user's machine then MSI
displays a msgbox "Another version of this product is already
installed.". But, in my case, this msgbox does not get displayed and
dialog is waiting for response, plz see the CODE below:
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CString strPath = ((CXAStartApp *)AfxGetApp())->GetAppPath();
CString strSetupPath = strPath + "\\Setup*.msi";
CFileFind finder;
if (finder.FindFile(strSetupPath))
{
finder.FindNextFile();
strSetupPath = finder.GetFilePath();
STARTUPINFO StartupInfo = {0};
PROCESS_INFORMATION ProcessInfo = {0};
StartupInfo.cb = sizeof(STARTUPINFO);
StartupInfo.dwFlags = STARTF_USESHOWWINDOW;
StartupInfo.wShowWindow = SW_HIDE;
char szSysPath[MAX_PATH];
GetSystemDirectory(szSysPath, MAX_PATH);
CString strExeName = szSysPath;
strExeName += "\\msiexec.exe";
CString strCmdLine = "msiexec /i \"";
strCmdLine += strSetupPath;
strCmdLine += "\"";
char szCmdLine[MAX_PATH];
strcpy(szCmdLine, (LPCTSTR)strCmdLine);
BOOL retvalue = CreateProcess(strExeName, szCmdLine, NULL, NULL,
FALSE, 0, NULL, strPath, &StartupInfo, &ProcessInfo);
HANDLE hProcess = ProcessInfo.hProcess;
Sleep(1000);
while(1)
{
if(WaitForSingleObject(hProcess, 1250) == WAIT_OBJECT_0)
break;
}
}
OnOK();
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Plz help me to sort the problem.

Thanks in advance.

Regards,
Zia