doxysearch.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/bin/doxysearch.cgi - from package: doxygen

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

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