apache2 won't start on boot because of “no listening sockets available” error-Collection of common programming errors

When booting a debian wheezy server using apache2 version 2.2.22, the apache autostart fails with the following error:

Starting web server: apache2(99)Cannot assign requested address: make_sock: could not bind to address [2a01:aaa:bbb:ccc::2]:80
no listening sockets available, shutting down
Unable to open logs
Action 'start' failed.

I already checked if port 80 is already being used by another process using netstat – it is not.

The ipv6 setup is native, not using any tunnels. This is the used /etc/network/interfaces:

iface eth0 inet6 static
  address 2a01:aaa:bbb:ccc::2
  netmask 64
  gateway 2a01:aaa:bbb:ccc::1

I also tried setting the S[xx]apache2 number used by rc.d higher then the ones of all the other process, still the same error.

When later starting apache manually using /etc/init.d/apache2 start over ssh, everything works fine.

How could I possibly fix this?