1. You need two terminal windows.
2. Start the first instance, just amaya on the first terminal window
   (If you do nothing described below, you will wait forever to something happens).
3. On second terminal windows, start the second instance. You will get the error as:

   pinapa@makoto 23:14:07/130421(~)% amaya
   23:14:49: Error: Another instance is running
   load: 0.41  cmd: amaya_bin 27780 [runnable] 6.05u 2.66s 34% 16268k
   

   You will soon get [runnable] with Control-T.
4. In the second terminal, you will kill the second instance by Control-C.
5. From the first terminal invocation, You will get [runnable] status by Control-T, and soon Amaya window will appear.

But having the message on the first terminal:

libpng error: png_start_read_image/png_read_update_info: duplicate call

#0  0x00007f7ff784c197 in glRenderMode () from /usr/pkg/lib/libGL.so.1
#1  0x000000000067b1f5 in SetMainWindowBackgroundColor(int, int) ()
#2  0x00000000005a87b6 in CreateBox(_AbstractBox*, int, bool, bool, int*, int) ()
#3  0x00000000005aa13d in ComputeUpdates(_AbstractBox*, int, bool*) ()
#4  0x00000000005ac0fa in IsAbstractBoxUpdated(_AbstractBox*, int, bool*) ()
#5  0x00000000005ad0ed in ChangeConcreteImage(int, int*, _AbstractBox*) ()
#6  0x00000000005ccb6b in RebuildImage(_DocumentDescr*) ()
#7  0x00000000005cddc2 in TtaSetDisplayMode(int, _DisplayMode) ()
#8  0x00000000004c8a0b in InitView(int, int, bool, bool, bool, int, int, int, DocumentType, int) ()
#9  0x00000000004ca2ac in InitDocAndView(int, bool, bool, char const*, DocumentType, int, bool, int, int, int) ()
#10 0x000000000047bd77 in NotFoundDoc(char*, int) ()
#11 0x00000000004cfc1e in CallbackDialogue(int, int, char*) ()
#12 0x00000000004cfebd in OpenNewDocFromArgv(char*) ()
#13 0x00000000004d297f in InitAmaya(NotifyEvent*) ()
#14 0x000000000061d1b3 in CallAction(NotifyEvent*, APPevent, bool, int, int*, _StructSchema*, bool) ()
#15 0x000000000061d287 in CallEventType(NotifyEvent*, bool) ()
#16 0x00000000006296e4 in TtaMainLoop() ()
#17 0x0000000000471e91 in amaya_main(int, char**) ()
#18 0x00000000005e067e in AmayaApp::OnIdle(wxIdleEvent&) ()
#19 0x00007f7ff3cd760a in
   wxEvtHandler::ProcessEventIfMatches(wxEventTableEntryBase
   const&, wxEvtHandler*, wxEvent&) () from
   /usr/pkg/lib/libwx_baseu-2.8.so.0
#20 0x00007f7ff3cd771c in
   wxEventHashTable::HandleEvent(wxEvent&, wxEvtHandler*) ()
   from /usr/pkg/lib/libwx_baseu-2.8.so.0
#21 0x00007f7ff3cd79d7 in wxEvtHandler::ProcessEvent(wxEvent&) () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#22 0x00007f7ff4e35987 in wxAppBase::ProcessIdle() () from /usr/pkg/lib/libwx_gtk2u_core-2.8.so.0
#23 0x00007f7ff4dbc2b1 in wxApp::Yield(bool) () from /usr/pkg/lib/libwx_gtk2u_core-2.8.so.0
#24 0x00007f7ff441e897 in wxSocketBase::_Wait(long, long, int) () from /usr/pkg/lib/libwx_baseu_net-2.8.so.0
---Type <return> to continue, or q <return> to quit--- 
#25 0x00007f7ff441f015 in wxSocketBase::_Read(void*, unsigned int) () from /usr/pkg/lib/libwx_baseu_net-2.8.so.0
#26 0x00007f7ff441f320 in wxSocketBase::Read(void*, unsigned int) () from /usr/pkg/lib/libwx_baseu_net-2.8.so.0
#27 0x00007f7ff441dd7d in
    wxSocketInputStream::OnSysRead(void*, unsigned long) () from
    /usr/pkg/lib/libwx_baseu_net-2.8.so.0
#28 0x00007f7ff3ca7016 in wxInputStream::Read(void*, unsigned long) () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#29 0x00007f7ff3c71e57 in wxDataInputStream::Read8() () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#30 0x00007f7ff441d126 in
    wxTCPEventHandler::Server_OnRequest(wxSocketEvent&) () from
    /usr/pkg/lib/libwx_baseu_net-2.8.so.0
#31 0x00007f7ff3cd760a in
    wxEvtHandler::ProcessEventIfMatches(wxEventTableEntryBase
    const&, wxEvtHandler*, wxEvent&) () from
    /usr/pkg/lib/libwx_baseu-2.8.so.0
#32 0x00007f7ff3cd771c in
    wxEventHashTable::HandleEvent(wxEvent&, wxEvtHandler*) ()
    from /usr/pkg/lib/libwx_baseu-2.8.so.0
#33 0x00007f7ff3cd79d7 in wxEvtHandler::ProcessEvent(wxEvent&) () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#34 0x00007f7ff3cd757e in wxEvtHandler::ProcessPendingEvents() () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#35 0x00007f7ff3c63777 in wxAppConsole::ProcessPendingEvents() () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#36 0x00007f7ff4e3590e in wxAppBase::ProcessIdle() () from /usr/pkg/lib/libwx_gtk2u_core-2.8.so.0
#37 0x00007f7ff4dbb8fa in wxapp_idle_callback () from /usr/pkg/lib/libwx_gtk2u_core-2.8.so.0
#38 0x00007f7fe8c41c44 in g_main_context_dispatch () from /usr/pkg/lib/libglib-2.0.so.0
#39 0x00007f7fe8c41f1d in ?? () from /usr/pkg/lib/libglib-2.0.so.0
#40 0x00007f7fe8c42295 in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#41 0x00007f7fef12b854 in gtk_main () from /usr/pkg/lib/libgtk-x11-2.0.so.0
#42 0x00007f7ff4dcdc0a in wxEventLoop::Run() () from /usr/pkg/lib/libwx_gtk2u_core-2.8.so.0
#43 0x00007f7ff4e35759 in wxAppBase::MainLoop() () from /usr/pkg/lib/libwx_gtk2u_core-2.8.so.0
#44 0x00007f7ff3c8f258 in wxEntry(int&, wchar_t**) () from /usr/pkg/lib/libwx_baseu-2.8.so.0
#45 0x00000000005e0705 in main ()

#0 0x00007f7ff784c197 in glRenderMode () from /usr/pkg/lib/libGL.so.1 comes from MesaLib-7.4.4