Upgrading apache2 on Debian Etch “broke” the BackupPC apache.conf:
Starting web server (apache2)...Syntax error on line 9 of /etc/backuppc/apache.conf: Invalid command 'AuthGroupFile', perhaps misspelled or defined by a module not included in the server configuration failed! Starting web server (apache2)...Syntax error on line 10 of /etc/backuppc/apache.conf: Invalid command 'AuthUserFile', perhaps misspelled or defined by a module not included in the server configuration failed!
This problem seems to be due to a change in the way that some of the apache2 modules are handled. I needed to make symbolic links for the following modules from mods-available to mods-enabled–some of these may not be essential.
authn_file.load auth_basic.load auth_plain.load authz_dbm.load authz_default.load authz_groupfile.load authz_host.load authz_owner.load authz_user.load