htags: 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/htags - from package: global

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

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