unsplit: 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/lib/cmtk/bin/unsplit - from package: cmtk

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

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