I'm trying to install VHCS, It's supposed to have many features but so far it's had many errors

I think I only have to get past 1 more error to install this.
Here it is:
When I run the vhcs2-setup, it goes through a series of questions and after I type in the admin email address it tells me:
ERROR: Unknown user `www-data` !

I know that this is supposed to be wwwrun but I'm not sure how to change it.
Anybody know about this?