gaphorconvert: 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/gaphorconvert - from package: gaphor

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

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