condor_collector: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/sbin/condor_collector - from package: condor

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/condor_collector - from package: htcondor

You may install the required package with command apt-get install {package}

Error in other languages:
condor_collector: bevel nie gevind nie
condor_collector: comandă negăsită
condor_collector: comando não encontrado
condor_collector: commande introuvable
condor_collector: command not found
condor_collector: käsku ei ole
condor_collector: không tìm thấy lệnh
condor_collector: komanda nerasta
condor_collector: Kommando nicht gefunden.
condor_collector: kommandot finns inte
condor_collector: komut yok
condor_collector: nie znaleziono polecenia
condor_collector: níor aimsíodh an t-ordú
condor_collector: no se encontró la orden
condor_collector: no s'ha trobat l'ordre
condor_collector: opdracht niet gevonden
condor_collector: parancs nem található
condor_collector: perintah tidak ditemukan
condor_collector: príkaz nenájdený
condor_collector: příkaz nenalezen
condor_collector: команда не найдена
condor_collector: командата не е открита
condor_collector: 命令找不到
condor_collector: コマンドが見つかりません