project Center ( Icon for Documents Not Appearing )

[MIM]

Dear All

May Some Help me,
Tell me Why after uploading documents to projects in the projects workspace.
the ICON's that shows that documents are uploaded to the specified project
in the project center are not appearing, also couter still remain eaqual to
ZERO in the field Document,
in the other side if you go to Project Documents ' Document uploaded is
available'

Thank you in Advance

MIM
Project Server (PMO)