xmlif: 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/bin/xmlif - from package: xmlto

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

On Debian possible default full paths are:

/usr/bin/xmlif - from package: xmlto

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