minicom: 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 CentOS possible default full paths are:

/usr/bin/minicom - from package: minicom

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

On Debian possible default full paths are:

/usr/bin/minicom - from package: minicom

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

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