Comment 9 for bug 371147

The lines in question that are the problem are:

        if ((m->ptr = mmap(NULL, m->size, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, (off_t) 0)) == MAP_FAILED) {
            pa_log("mmap() failed: %s", pa_cstrerror(errno));
            goto fail;
        }

It should be easy enough to check to see if shared memory is in use, just run:

 mount | grep "shm"

If you get something like the following, then it's enabled:

tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)