lkbib: 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 CentOS possible default full paths are:

/usr/bin/lkbib - from package: groff

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/lkbib - from package: groff

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

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