unihex2bmp: 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/unihex2bmp - from package: unifont-bin

You may install the required package with command apt-get install {package}
Error in other languages:
unihex2bmp: bevel nie gevind nie
unihex2bmp: comandă negăsită
unihex2bmp: comando não encontrado
unihex2bmp: commande introuvable
unihex2bmp: command not found
unihex2bmp: käsku ei ole
unihex2bmp: không tìm thấy lệnh
unihex2bmp: komanda nerasta
unihex2bmp: Kommando nicht gefunden.
unihex2bmp: kommandot finns inte
unihex2bmp: komut yok
unihex2bmp: nie znaleziono polecenia
unihex2bmp: níor aimsíodh an t-ordú
unihex2bmp: no se encontró la orden
unihex2bmp: no s'ha trobat l'ordre
unihex2bmp: opdracht niet gevonden
unihex2bmp: parancs nem található
unihex2bmp: perintah tidak ditemukan
unihex2bmp: príkaz nenájdený
unihex2bmp: příkaz nenalezen
unihex2bmp: команда не найдена
unihex2bmp: командата не е открита
unihex2bmp: 命令找不到
unihex2bmp: コマンドが見つかりません