With other linux distros, I usually peruse /var/log files to see if
my system is complaining about anything. In my copy of Knoppix 6.2.1
/var/log is almost bare, except for Xorg.0.log and a puny pm... file.
Nothing very surprising there. But there is another (hidden) file I'd
never been aware of before in /home/knoppix, that is .xsession-errors.

In my case, this little gem, had accumulated two megs of notes over
a week or so of many, many boot-ups (probably over a hundred boots).
For the most part, I had thought my 6.2.1 system was behaving pretty
well, before I began examining this file. But, there is a lot to
learn here. By studying this file line-by-line and doing some
googling you can discover by yourself many tweaks that may reduce
these 'errors'.

I suspect many of these 'errors' are harmless; however, there if this
file gets out-of-hand, it could conceivably become a memory problem.
And, it could also be the case that hidden in this clutter of harmless
'error' indications are some real problems. For this reason, it is
well to clear these up and get rid of them, if possible.

It might also be useful to establish a FAQ relating to frequently-found
.xsession-errors and their solutions, assuming it's not here already
and I've missed it.