unixclient: 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 Debian possible default full paths are:

/usr/bin/unixclient - from package: ucspi-unix

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

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