gsm0710muxd: 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/sbin/gsm0710muxd - from package: fso-gsm0710muxd
/usr/sbin/gsm0710muxd - from package: gsm0710muxd

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

Error in other languages:
gsm0710muxd: bevel nie gevind nie
gsm0710muxd: comandă negăsită
gsm0710muxd: comando não encontrado
gsm0710muxd: commande introuvable
gsm0710muxd: command not found
gsm0710muxd: käsku ei ole
gsm0710muxd: không tìm thấy lệnh
gsm0710muxd: komanda nerasta
gsm0710muxd: Kommando nicht gefunden.
gsm0710muxd: kommandot finns inte
gsm0710muxd: komut yok
gsm0710muxd: nie znaleziono polecenia
gsm0710muxd: níor aimsíodh an t-ordú
gsm0710muxd: no se encontró la orden
gsm0710muxd: no s'ha trobat l'ordre
gsm0710muxd: opdracht niet gevonden
gsm0710muxd: parancs nem található
gsm0710muxd: perintah tidak ditemukan
gsm0710muxd: príkaz nenájdený
gsm0710muxd: příkaz nenalezen
gsm0710muxd: команда не найдена
gsm0710muxd: командата не е открита
gsm0710muxd: 命令找不到
gsm0710muxd: コマンドが見つかりません