extract_chmLib: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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 CentOS possible default full paths are:

/usr/bin/extract_chmLib - from package: chmlib

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/extract_chmLib - from package: libchm-bin

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