gnc-fq-helper: 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 CentOS possible default full paths are:

/usr/bin/gnc-fq-helper - from package: gnucash

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

On Debian possible default full paths are:

/usr/bin/gnc-fq-helper - from package: gnucash

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

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