graph-qeps.pl: 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/share/doc/librdf-query-perl/examples/bin/graph-qeps.pl - from package: librdf-query-perl

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

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