Installation problem on Synology "username already exits)



Hi guys,

I am trying last few days install owncloud-package on Synology but I face a curious problem on finishing installation on 1st login


After installation the package (Owncloud 8.1) while log in (1st time) I get response "Fail username already exits" (in Dutch "Fout de gebruikersnaam bestaat al"

I've taken the following steps:
1. Installation MariaDB (MySQL)
1. Installation Package Owncloud version 8.1.1-7
2. Check package-center: Owncloud is working
3. In webservice, add hostname "owncloud" httpserver Apach 2.2, PHP 5.6
4. Set permissions for HTTP-user (group) on owncloud directory: read/write
3. Starting Owncloud with URL http://[nas]/owncloud/index.php
4. Failure login "admin", username already exists

Can anybody tell me what is going wrong?