myproxy-get-trustroots: command not found

Have You tried accessing the binary with the full path?

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/myproxy-get-trustroots - from package: myproxy

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

On Debian possible default full paths are:

/usr/bin/myproxy-get-trustroots - from package: myproxy

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