ingo-convert-prefs-to-sql: 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/ingo-convert-prefs-to-sql - from package: php-horde-ingo

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

On Debian possible default full paths are:

/usr/bin/ingo-convert-prefs-to-sql - from package: php-horde-ingo

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

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