I'm in a similar situation.
Anyway, to solve your problem, make a directory called "id1" in /usr/share/games/quakeforge, then copy the pak files from the quake install to the id1 directory you just created, making sure they have lower case names.
When you run quake again, it should load.
However, I notice this line in your console:
Could not load plugin "/usr/lib/games/quakeforge/plugins/console_client.so"
Bad news I'm afraid.
According to this
post I found, it looks like a bit of editing, and a recompile of the quake source code
is in order.
When I figure out whats involved, I'll post what I did to get it working.