[xwiki-users] Cannot add users in XWiki

Hi all, I have been working for some time now with XWiki 6.3. Basically all the functionalities were OK. The wiki contains about 6 virtual wiki's, and all of them are up and running well. From a certain moment on, however, I noticed that I could not add any users to the main xwiki instance (I can add them to the virtual wiki's though). I am not aware of any change on the main-wiki (xwiki....) level that I might have caused. So I decided to upgrade to version 7.0 The upgrade process went well, but I still have this error. The error on the add-users page in xwiki in a pink message popup: Failed to execute the [velocity] macro. Click on the message for details. If I click on the message, there is no reaction. I can only close this popup. In the xwiki-log on the server I can read: 2015-04-16 19:29:24,968 [http://xwiki.-------.--/xwiki/bin/view/XWiki/XWikiPreferences?xpage=registe…] ERROR o.x.v.i.DefaultVelocityEngine - Exception in macro #loadConfig called at 19:xwiki:XWiki.Registration[line 19, column 1] Any ideas on how to get this functioning would be highly appreciated, as I will have to enter about 670 users with different rights on the different virtual-wikis. Cheers, Rui Rosado