arabic.txt: 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/gfxboot/themes/KDE/po/bin/arabic.txt - from package: gfxboot-themes
/usr/share/gfxboot/themes/openSUSE/po/bin/arabic.txt - from package: gfxboot-themes
/usr/share/gfxboot/themes/SLED/po/bin/arabic.txt - from package: gfxboot-themes
/usr/share/gfxboot/themes/SLES/po/bin/arabic.txt - from package: gfxboot-themes
/usr/share/gfxboot/themes/upstream/po/bin/arabic.txt - from package: gfxboot-themes

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

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