sp_preproc: 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/sp_preproc - from package: perl-SystemPerl

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

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