visual-regexp: 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/visual-regexp - from package: visual-regexp

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

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