horde-db-migrate-component: 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/horde-db-migrate-component - from package: php-horde-Horde-Db

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

On Debian possible default full paths are:

/usr/bin/horde-db-migrate-component - from package: php-horde-db

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

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