ocat: command not found

Have You tried accessing the binary with the full path?

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 Debian possible default full paths are:

/usr/bin/ocat - from package: onioncat

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