Installation problem

[billy2e]

[root@ispcp setup]# perl ispcp-setup

Welcome to ispCP '1.0.0 RC6 OMEGA' Setup Dialog.
This program will set up ispCP OMEGA system on your server.

Next you are asked to enter a "fully qualified hostname" (FQHN).
For more infos read http://en.wikipedia.org/wiki/FQDN.


Please enter a fully qualified hostname. [ispcp.xxx.com]:

Please enter system network address. [xxx.xxx.xxx.xxx]:

Please enter the domain name where ispCP OMEGA will run on [admin.ispcp.xxx.com]:

Please enter SQL server host. [localhost]:

Please enter system SQL database. [ispcp]:

Please enter system SQL user. [root]:

Please enter system SQL password. [none]:
Please repeat system SQL password:

Please enter ispCP ftp SQL user. [vftp]:

Please enter ispCP ftp SQL user password. [auto generate]:
ispCP ftp SQL user password set to: t!.^_/2vyU8YQjy]O%

Please enter ispCP phpMyAdmin Control user. [pma]:

Please enter ispCP phpMyAdmin Control user password. [auto generate]:
phpMyAdmin Control user password set to: )z3P0:UXef1*3+00mY

Please enter administrator login name. [admin]:

Please enter administrator password:

Password too short!
Please enter administrator password:
Please repeat administrator password:

Please enter administrator e-mail address: billy@vpsmart.com

IP of Secondary DNS. (optional) []:

Use MySQL Prefix.
Possible values: [i]nfront, [b]ehind, [n]one. [none]:

FastCGI Version:[f]astcgi or f[c]gid. [fastcgi]:

Activate AWStats. [no]: yes

AWStats Mode:
Possible values [d]ynamic and [s]tatic. [dynamic]:

Starting Installation...
Can't exec "which": No such file or directory at ispcp-setup-methods.pl line 652.
Can't exec "which": No such file or directory at ispcp-setup-methods.pl line 653.
Use of uninitialized value in substitution (s///) at ispcp-setup-methods.pl line 655.
Use of uninitialized value in substitution (s///) at ispcp-setup-methods.pl line 656.
Use of uninitialized value in length at ispcp-setup-methods.pl line 658.
Use of uninitialized value in length at ispcp-setup-methods.pl line 658.
ERROR: Undefined template replacement data in repl_var: {RKHUNTER}!

i am using centos 5.2 os.
please help!!THX
if you know what happen, please contact billy2e@gmail.com.