In contrast to the problem described in my previous post this one was directly related to the OS X 10.4 (Tiger) to 10.5 (Leopard) upgrade.
After the upgrade I tried to install a software packet through MacPort’s
port command. The pile of error and warning messages left me puzzled at first:
checking for working aclocal-1.4... missing
checking for working automake-1.4... missing
Then I found out that XCode is not automatically updated during the 10.4 -> 10.5 installation. Hence, I needed to uninstall the old XCode and install XCode 3 from the Leopard DVD.