gtrial: 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/gtrial - from package: python-qt4reactor

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

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