I wonder if this could be a memory allocation issue? See this short thread for a much earlier release, where the OP posting included your error message, and I also posted there my /etc/security/limits.conf additions which I have always needed for jack, up to and including openSUSE 13.1 (but not using Ardour). Note the solution found by the OP in post #5:
https://forums.opensuse.org/showthread.php/449632-Jack2-cannot-allocate-memory