Error when calling protected APIs requiring Programming Rights.

I logged in using Admin account with programming rights.
To override the Flamingo skin, I created a new Skin Object ( XWiki.XWikiSkins object).

To override some template (vm) of the Flamingo skin I added a property to the skin object that has the following XWQL query:

#set($query = "select oright.groups from Document doc, doc.object(ProjectsCode.ProjectsCodeClass) as prj, doc.object(XWiki.XWikiRights) as oright where oright.levels like :levels and oright.allow=1 and oright.groups <> ''")
#set($results = $services.query.xwql($query).bindValue("levels","%edit%").execute())

Everything is ok for the Admin user, but with a not admin user I got the following error when opening some pages:
Caused by: org.xwiki.query.QueryException: Full form statements requires programming right. Query statement =

Note that:
1) This issue is not appeared in the home page (Main.WebHome) even for not Admin users.
2) I created a test page in SandBox space and I execute the query, there is no issue for all users.
3) XWiki Version 6.2.2