(CentOS) ERROR: Unknown user 'www-data' !

[joximu]

since the setup never finished, you have nothing to loose :-)

to be sure: run the script "reset-setup" (in the setup folder).

Then:
- delete the ispcp in /tmp (if something is still there)
- do the make command again in the folder where you unpacked the downloaded file...
-with "-f Makefile.centos" of course...
- then follow the INSTALL doc (copy from /tmp/ispcp to /, mysql root pw should already be set, so you then can got to the step ispcp-setup (if I remeber right :-)

/J