tbl: 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/tbl - from package: groff

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

On Debian possible default full paths are:

/usr/bin/tbl - from package: groff-base

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

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