|of-course yes. You can invoke a modal dialog from another modal dialog. Coming to your problem there is something wrong with the usage of CFileDialog. can you paste the complete exception stack/message so that we can able find what went wrong.
I took this sample from here[^] hope you are doing the same. if not give a try.
dlgFile.GetOFN().lpstrFile = fileName.GetBuffer(<very large number&>);
dlgFile.GetOFN().nMaxFile = <very large number >;
INT_PTR nResult = dlgFile.DoModal();
Read these lines carefully
The destruction of CFileDialog objects is handled automatically. It is not necessary to call CDialog::EndDialog.
To allow the user to select multiple files, set the OFN_ALLOWMULTISELECT flag before calling DoModal. You need to supply your own filename buffer to accommodate the returned list of multiple filenames. Do this by replacing m_ofn.lpstrFile with a pointer to a buffer you have allocated, after constructing the CFileDialog, but before calling DoModal.
When the user allocates their own buffer to accommodate OFN_ALLOWMULTISELECT, the buffer can't be larger than 2048 or else everything gets corrupted (2048 is the maximum size).
Additionally, you must set m_ofn.nMaxFile with the number of characters in the buffer pointed to by m_ofn.lpstrFile. If you set the maximum number of files to be selected to n, the necessary buffer size is n*(_MAX_PATH + 1) + 1.