pcp-dmcache: 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-dmcache - 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-dmcache - from package: pcp

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

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