kde4-doxygen.sh: 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 CentOS possible default full paths are:

/usr/bin/kde4-doxygen.sh - from package: kdelibs-devel

You may install the required package with command yum install {package}

Error in other languages:
kde4-doxygen.sh: bevel nie gevind nie
kde4-doxygen.sh: comandă negăsită
kde4-doxygen.sh: comando não encontrado
kde4-doxygen.sh: commande introuvable
kde4-doxygen.sh: command not found
kde4-doxygen.sh: käsku ei ole
kde4-doxygen.sh: không tìm thấy lệnh
kde4-doxygen.sh: komanda nerasta
kde4-doxygen.sh: Kommando nicht gefunden.
kde4-doxygen.sh: kommandot finns inte
kde4-doxygen.sh: komut yok
kde4-doxygen.sh: nie znaleziono polecenia
kde4-doxygen.sh: níor aimsíodh an t-ordú
kde4-doxygen.sh: no se encontró la orden
kde4-doxygen.sh: no s'ha trobat l'ordre
kde4-doxygen.sh: opdracht niet gevonden
kde4-doxygen.sh: parancs nem található
kde4-doxygen.sh: perintah tidak ditemukan
kde4-doxygen.sh: príkaz nenájdený
kde4-doxygen.sh: příkaz nenalezen
kde4-doxygen.sh: команда не найдена
kde4-doxygen.sh: командата не е открита
kde4-doxygen.sh: 命令找不到
kde4-doxygen.sh: コマンドが見つかりません