gpiv_sstrain: 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/gpiv_sstrain - from package: gpivtools-mpi
/usr/bin/gpiv_sstrain - from package: gpivtools

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

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