simsearch: 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/simsearch - from package: python-chemfp

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

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