perfdata.cgi: 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/lib/xymon/server/bin/perfdata.cgi - from package: xymon

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

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