deparse.pl: command not found

Have You tried accessing the binary with the full path?

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/deparse.pl - from package: librdf-query-perl

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