pcp-uptime: 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/libexec/pcp/bin/pcp-uptime - from package: pcp-system-tools

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

On Debian possible default full paths are:

/usr/lib/pcp/bin/pcp-uptime - from package: pcp

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

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