dateutils.dseq: 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/bin/dateutils.dseq - from package: dateutils

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