qemu-mipsel: 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/qemu-mipsel - from package: qemu-user

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