CRM Importing Issue

Question

Dear all

       i am working in CRM 4.0..when i am trying to import the XML file to my crm organization, its showing the error

error:
either the file could not be uploaded or this is not a valid customization file

i took this xml file from the Client system and trying to import, but its showing error.Where i am going wrong, is there any possibilities to restrict the import option from the client side..please help me out

Regards

Arun