qcomicbook: 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/bin/qcomicbook - from package: qcomicbook

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

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