primer_designer: 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/primer_designer - from package: libbio-primerdesigner-perl

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

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