why the request url works only for Admin rigts users not for  non admin users

Hi ,

I have  a request url that works for the users who have admin rights .

<a href= "#" onClick = "{Dialog.getMainWindow().location = '/aveksa/main?ReqType=Dialog&PageID=RequestSourcesAddWizard&Action=New&CRButton=6&targetUser=${avform.user.User_Id}';} return false;" rel= "nofollow"><b>CLICK HERE</b></a> to start a new request.

but why this is not working with NON Admin users and if i click on the select application i am getting "insufficient privileges" error page.

How can we resolve this issue and make this url to work for every user?