tc2html-toc: 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/tc2html-toc - from package: troffcvt

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

Error in other languages:
tc2html-toc: bevel nie gevind nie
tc2html-toc: comandă negăsită
tc2html-toc: comando não encontrado
tc2html-toc: commande introuvable
tc2html-toc: command not found
tc2html-toc: käsku ei ole
tc2html-toc: không tìm thấy lệnh
tc2html-toc: komanda nerasta
tc2html-toc: Kommando nicht gefunden.
tc2html-toc: kommandot finns inte
tc2html-toc: komut yok
tc2html-toc: nie znaleziono polecenia
tc2html-toc: níor aimsíodh an t-ordú
tc2html-toc: no se encontró la orden
tc2html-toc: no s'ha trobat l'ordre
tc2html-toc: opdracht niet gevonden
tc2html-toc: parancs nem található
tc2html-toc: perintah tidak ditemukan
tc2html-toc: príkaz nenájdený
tc2html-toc: příkaz nenalezen
tc2html-toc: команда не найдена
tc2html-toc: командата не е открита
tc2html-toc: 命令找不到
tc2html-toc: コマンドが見つかりません