mips64el-linux-gnuabi64-readelf: 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 Debian possible default full paths are:

/usr/bin/mips64el-linux-gnuabi64-readelf - from package: binutils-mips64el-linux-gnuabi64

You may install the required package with command apt-get install {package}
Error in other languages:
mips64el-linux-gnuabi64-readelf: bevel nie gevind nie
mips64el-linux-gnuabi64-readelf: comandă negăsită
mips64el-linux-gnuabi64-readelf: comando não encontrado
mips64el-linux-gnuabi64-readelf: commande introuvable
mips64el-linux-gnuabi64-readelf: command not found
mips64el-linux-gnuabi64-readelf: käsku ei ole
mips64el-linux-gnuabi64-readelf: không tìm thấy lệnh
mips64el-linux-gnuabi64-readelf: komanda nerasta
mips64el-linux-gnuabi64-readelf: Kommando nicht gefunden.
mips64el-linux-gnuabi64-readelf: kommandot finns inte
mips64el-linux-gnuabi64-readelf: komut yok
mips64el-linux-gnuabi64-readelf: nie znaleziono polecenia
mips64el-linux-gnuabi64-readelf: níor aimsíodh an t-ordú
mips64el-linux-gnuabi64-readelf: no se encontró la orden
mips64el-linux-gnuabi64-readelf: no s'ha trobat l'ordre
mips64el-linux-gnuabi64-readelf: opdracht niet gevonden
mips64el-linux-gnuabi64-readelf: parancs nem található
mips64el-linux-gnuabi64-readelf: perintah tidak ditemukan
mips64el-linux-gnuabi64-readelf: príkaz nenájdený
mips64el-linux-gnuabi64-readelf: příkaz nenalezen
mips64el-linux-gnuabi64-readelf: команда не найдена
mips64el-linux-gnuabi64-readelf: командата не е открита
mips64el-linux-gnuabi64-readelf: 命令找不到
mips64el-linux-gnuabi64-readelf: コマンドが見つかりません