I'm sorry I cannot reproduce the output here, but when I "startx" as a non-root
user on my 4.5/amd64/bsd.mp box (not -stable, but the stock install), several
errors are displayed (in paraphrase):
1. "X is already running on the console" -- though I have just logged in after
a reboot.
2. "Can't create /tmp/<some-file>" -- /tmp is mounted as mfs under swap, like
so:
swap /tmp mfs rw,nodev,nosuid,-s=153600 0 0
There are others I cannot even remember in paraphrase, unfortunately.
That said, I have no problem with "startx" as root. My non-root user is already
added to group wheel, if that is notable.
Thanks.