rbuic4: 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/rbuic4 - from package: ruby-qt4

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

Error in other languages:
rbuic4: bevel nie gevind nie
rbuic4: comandă negăsită
rbuic4: comando não encontrado
rbuic4: commande introuvable
rbuic4: command not found
rbuic4: käsku ei ole
rbuic4: không tìm thấy lệnh
rbuic4: komanda nerasta
rbuic4: Kommando nicht gefunden.
rbuic4: kommandot finns inte
rbuic4: komut yok
rbuic4: nie znaleziono polecenia
rbuic4: níor aimsíodh an t-ordú
rbuic4: no se encontró la orden
rbuic4: no s'ha trobat l'ordre
rbuic4: opdracht niet gevonden
rbuic4: parancs nem található
rbuic4: perintah tidak ditemukan
rbuic4: príkaz nenájdený
rbuic4: příkaz nenalezen
rbuic4: команда не найдена
rbuic4: командата не е открита
rbuic4: 命令找不到
rbuic4: コマンドが見つかりません