pure-uploadscript: 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 CentOS possible default full paths are:

/usr/sbin/pure-uploadscript - from package: pure-ftpd

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/pure-uploadscript - from package: pure-ftpd-ldap
/usr/sbin/pure-uploadscript - from package: pure-ftpd-mysql
/usr/sbin/pure-uploadscript - from package: pure-ftpd-postgresql
/usr/sbin/pure-uploadscript - from package: pure-ftpd

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