fview: 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/lib/cmtk/bin/fview - from package: cmtk

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

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