Comment 4 for bug 1743064

ASSERT INFO:
../src/common/filefn.cpp(251): assert "!fn.IsDir()" failed in FindValidPath(): Cannot search for directories; only for files

BACKTRACE:
[1] wxPathList::FindValidPath(wxString const&) const
[2] wxPathList::FindAbsoluteValidPath(wxString const&) const
[3] HuginQueue::GetExternalProgram(wxConfigBase*, wxString const&, wxString const&)
[4] HuginQueue::detail::PrintDetailInfo(HuginBase::Panorama const&, HuginBase::PanoramaOptions const&, std::set<unsigned int, std::less<unsigned int>, std::allocator<unsigned int> > const&, wxString const&, wxString const&, wxConfigBase*, double&)
[5] HuginQueue::GetStitchingCommandQueue(HuginBase::Panorama const&, wxString const&, wxString const&, wxString const&, wxString&, wxArrayString&, wxArrayString&)
[6] RunStitchPanel::StitchProject(wxString, wxString)
[7] RunStitchFrame::StitchProject(wxString, wxString)
[8] Batch::OnStitch(wxString, wxString, int)
[9] Batch::RunNextInBatch()
[10] Batch::RunBatch()
[11] BatchFrame::RunBatch()
[12] PTBatcherGUI::OnInit()
[13] wxEntry(int&, wchar_t**)
[14] main
[15] __libc_start_main
[16] _start