dpkg-trigger: 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/dpkg-trigger - from package: dpkg

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

On Debian possible default full paths are:

/usr/bin/dpkg-trigger - from package: dpkg

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

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