gpsketcher: 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/gpsketcher - from package: libgtk2-gladexml-simple-perl

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

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