kbibtex: 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/kbibtex - from package: kbibtex

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

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