pregap4: 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/bin/pregap4 - from package: staden
/usr/lib/staden/bin/pregap4 - from package: staden

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

Error in other languages:
pregap4: bevel nie gevind nie
pregap4: comandă negăsită
pregap4: comando não encontrado
pregap4: commande introuvable
pregap4: command not found
pregap4: käsku ei ole
pregap4: không tìm thấy lệnh
pregap4: komanda nerasta
pregap4: Kommando nicht gefunden.
pregap4: kommandot finns inte
pregap4: komut yok
pregap4: nie znaleziono polecenia
pregap4: níor aimsíodh an t-ordú
pregap4: no se encontró la orden
pregap4: no s'ha trobat l'ordre
pregap4: opdracht niet gevonden
pregap4: parancs nem található
pregap4: perintah tidak ditemukan
pregap4: príkaz nenájdený
pregap4: příkaz nenalezen
pregap4: команда не найдена
pregap4: командата не е открита
pregap4: 命令找不到
pregap4: コマンドが見つかりません