ppmtoxvmini: 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/ppmtoxvmini - from package: makexvpics

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