If the error message "./Configure: not found" occurs during a tape installation, it is likely that the autorewinding tape drive was given as the name of the tape device during installation. To fix this, rerun the installation script and be sure to give the non-autorewinding device as listed by the installation script.
If a tape installation seems to take longer than 30-40 minutes on AIX, it may be that the block size of the tape size is set to 0. If this is the case, use "smit", AIX's System Management Interface Tool, to change the block size of the device to 512 bytes.