cvs-clean: 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/cvs-clean - from package: kdesdk

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

On Debian possible default full paths are:

/usr/bin/cvs-clean - from package: kdesdk-scripts

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

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