am7xxx-modeswitch: 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/am7xxx-modeswitch - from package: libam7xxx0.1-bin

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

Error in other languages:
am7xxx-modeswitch: bevel nie gevind nie
am7xxx-modeswitch: comandă negăsită
am7xxx-modeswitch: comando não encontrado
am7xxx-modeswitch: commande introuvable
am7xxx-modeswitch: command not found
am7xxx-modeswitch: käsku ei ole
am7xxx-modeswitch: không tìm thấy lệnh
am7xxx-modeswitch: komanda nerasta
am7xxx-modeswitch: Kommando nicht gefunden.
am7xxx-modeswitch: kommandot finns inte
am7xxx-modeswitch: komut yok
am7xxx-modeswitch: nie znaleziono polecenia
am7xxx-modeswitch: níor aimsíodh an t-ordú
am7xxx-modeswitch: no se encontró la orden
am7xxx-modeswitch: no s'ha trobat l'ordre
am7xxx-modeswitch: opdracht niet gevonden
am7xxx-modeswitch: parancs nem található
am7xxx-modeswitch: perintah tidak ditemukan
am7xxx-modeswitch: príkaz nenájdený
am7xxx-modeswitch: příkaz nenalezen
am7xxx-modeswitch: команда не найдена
am7xxx-modeswitch: командата не е открита
am7xxx-modeswitch: 命令找不到
am7xxx-modeswitch: コマンドが見つかりません