fastaq_replace_bases: 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
/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/fastaq_replace_bases - from package: fastaq

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