dotty: 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/dotty - from package: graphviz

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

On Debian possible default full paths are:

/usr/bin/dotty - from package: graphviz

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

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