gdcmanon: 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/gdcmanon - from package: libgdcm-tools

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

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