genhtmlidx.pl: 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/share/texlive/texmf-dist/source/latex/koma-script/doc/bin/genhtmlidx.pl - from package: texlive-latex-recommended

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

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