cvs-pserver: 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/share/gforge/plugins/scmcvs/sbin/cvs-pserver - from package: fusionforge-plugin-scmcvs

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

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