mmg crashed with signal 5 in raise()

[magowiz]

$ lsb_release -rd
Description: Ubuntu 15.04
Release: 15.04

$ apt-cache policy mkvtoolnix
mkvtoolnix:
  Installato: 7.3.0-1
  Candidato: 7.3.0-1
  Tabella versione:
 *** 7.3.0-1 0
        500 http://archive.ubuntu.com/ubuntu/ vivid/universe amd64 Packages
        100 /var/lib/dpkg/status

It crashed after serveral attempts to add a srt file to a mp4 file

ProblemType: Crash
DistroRelease: Ubuntu 15.04
Package: mkvtoolnix-gui 7.3.0-1 [modified: usr/bin/mkvinfo-gui usr/bin/mmg]
ProcVersionSignature: Ubuntu 3.19.0-16.16-generic 3.19.3
Uname: Linux 3.19.0-16-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Mon May 25 09:04:23 2015
ExecutablePath: /usr/bin/mmg
ProcCmdline: mmg
Signal: 5
SourcePackage: mkvtoolnix
StacktraceTop:
 raise (sig=5) at ../sysdeps/unix/sysv/linux/pt-raise.c:36
 ?? () from /usr/lib/x86_64-linux-gnu/libwx_baseu-3.0.so.0
 wxOnAssert(char const*, int, char const*, char const*, wchar_t const*) () from /usr/lib/x86_64-linux-gnu/libwx_baseu-3.0.so.0
 wxGUIAppTraits::ShowAssertDialog(wxString const&) () from /usr/lib/x86_64-linux-gnu/libwx_gtk2u_core-3.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libwx_baseu-3.0.so.0
Title: mmg crashed with signal 5 in raise()
UpgradeStatus: Upgraded to vivid on 2015-04-24 (31 days ago)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

StacktraceTop:
 raise (sig=5) at ../sysdeps/unix/sysv/linux/pt-raise.c:36
 wxDefaultAssertHandler (file=..., line=332, func=..., cond=..., msg=...) at ../src/common/appbase.cpp:1077
 wxOnAssert (file=file@entry=0x362216897c "../src/gtk/utilsgtk.cpp", line=line@entry=332, func=func@entry=0x3622168b30 <wxGUIAppTraits::ShowAssertDialog(wxString const&)::__FUNCTION__> "ShowAssertDialog", cond=cond@entry=0x3622160863 "Assert failure", msg=msg@entry=0x3622168a58 L"unexpected return code from GtkAssertDialog") at ../src/common/appbase.cpp:1178
 wxGUIAppTraits::ShowAssertDialog (this=<optimized out>, msg=...) at ../src/gtk/utilsgtk.cpp:332
 ShowAssertDialog (file=..., line=line@entry=456, func=..., cond=..., msgUser=..., traits=traits@entry=0x26fc770) at ../src/common/appbase.cpp:1302