rbqt4api: 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/rbqt4api - from package: ruby-qt4

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

Error in other languages:
rbqt4api: bevel nie gevind nie
rbqt4api: comandă negăsită
rbqt4api: comando não encontrado
rbqt4api: commande introuvable
rbqt4api: command not found
rbqt4api: käsku ei ole
rbqt4api: không tìm thấy lệnh
rbqt4api: komanda nerasta
rbqt4api: Kommando nicht gefunden.
rbqt4api: kommandot finns inte
rbqt4api: komut yok
rbqt4api: nie znaleziono polecenia
rbqt4api: níor aimsíodh an t-ordú
rbqt4api: no se encontró la orden
rbqt4api: no s'ha trobat l'ordre
rbqt4api: opdracht niet gevonden
rbqt4api: parancs nem található
rbqt4api: perintah tidak ditemukan
rbqt4api: príkaz nenájdený
rbqt4api: příkaz nenalezen
rbqt4api: команда не найдена
rbqt4api: командата не е открита
rbqt4api: 命令找不到
rbqt4api: コマンドが見つかりません