Installation failed... after Checking for MTA

[sushestvo]

I accepted License, then chose language and then this came up:
Do you accept the licence? [y/n]y

Please select the installation mode. In expert mode you have to answer some additional questions. In standard mode standard values are assumed for these questions.
1) standard
2) expert
Your Choice: 2

########## MAIL SERVER ##########

Checking for MTA...
./setup2: line 349: which: command not found
./setup2: line 349: which: command not found
ERROR: Your system configuration is not compatible with ISPConfig! The installation routine stops here!

System is FC3 and everything was installed prior running setup.
What this error means? (line 349)

[falko]

It means the program which is missing. Did you follow the tutorial for Fedora Core 3? On page 3 ( http://www.howtoforge.com/perfect_setup_fedora_core_3_p3 ) the program which is installed:
apt-get install which fetchmail wget bzip2 unzip zip nmap openssl lynx fileutils ncftp
If you didn't follow the tutorial or don't have apt installed, run
yum install which

[sushestvo]

I have apt installed.
And I'm pretty sure I have all those packages installed. Some through Apt, some through yum.
How can I check if I have a specific package? I would just check for all of them.

[falko]

Then run apt-get install which
It will tell you if the program is already installed.

[sushestvo]

Thanks! Everything was installed fine.