I can solve, at last. On Ubuntu 14.04 (i386), the libportmidi isn't fixed at 30 of november 2014. So, i take the debian jessie package an install it on ubuntu. But first i had to uninstall the ubuntu package. Now Mixxx dos't crash anymore and work ok with hercules Control AIR.
Steps
1) Remove libportmidi package from ubuntu (open synaptic, search libpormidi and uninstall it)
I can solve, at last. On Ubuntu 14.04 (i386), the libportmidi isn't fixed at 30 of november 2014. So, i take the debian jessie package an install it on ubuntu. But first i had to uninstall the ubuntu package. Now Mixxx dos't crash anymore and work ok with hercules Control AIR.
Steps
1) Remove libportmidi package from ubuntu (open synaptic, search libpormidi and uninstall it)
2) Download libportmidi deb from https:/ /packages. debian. org/jessie/ i386/libportmid i0/download and install it
3) Open Mixxx and check its ok