Have you checked that you have the latest version of your HP printer drivers installed, WrongCoaster?
If you
do a Google you'll find that HP printers and their drivers are often implicated in Mac sleep issues (though they are far from the sole cause) and I see HP mentioned in your log files.
If you have the HP launch agent installed in your "Log-in" items you might first try removing it and seeing whether the problem persists.
(There are many other possibilities with sleep issues, often involving out of date drivers or background software, so post back if this doesn't resolve it, but the info you have provided suggests the HP issue is worth checking out first)
Cheers
Rod