libIDL-config: 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/libIDL-config - from package: ORBit-devel

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

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