gce_gahp: 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/sbin/gce_gahp - from package: condor

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

On Debian possible default full paths are:

/usr/sbin/gce_gahp - from package: htcondor

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

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