viewvc-make-database: 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/sbin/viewvc-make-database - from package: viewvc-query

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

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