5.7 gave me the same error... I'm pretty sure that I'm missing the openacs web pages that are inccluded to install the application.
But I followed the install guide with no deviations... I even tried doint it a couple of times, with different distros, I always get to the same Not Found.
I'm wondering if this is the problem:
config.tls shows:
set server "pabloacs"
set serverroot "/var/www/${server}"
set pageroot ${serverroot}/www
Then all the pages should be stores on /var/www/pabloacs/www right? But there is nothing there, just the log folder:
pabloacs@debian:/var/lib/aolserver$ ls -l /var/www/pabloacs/
total 4
drwxr-xr-x 2 pabloacs pabloacs 4096 Dec 9 16:03 log
Should a change the "pageroot" variable?
Point to "/var/lib/aolserver/pabloacs/packages/acs-admin/www/" maybe?
