since I updated from Ubuntu 10.10 to 11.04 ardour crashes by a segfault. It happens to ardour2 shipped with ubuntu as well as to a self-built ardour3 from last week’s svn.
The stack trace of both crashes is almost identical and it seems to be some problem in gtk. Is this a known issue?
Try changing your theme in GTK and see if that makes a difference? Had someone with a similar symptoms that it fixed it for them, but it is hard to say for certain you are experiencing the same thing without seeing the backtrace.