This error means that the table is in use, so you must Select the table first, something like

lcSource = 'Z:\C13\tables\weights.dbf'
lcTarget = forcepath(lcSource,'E:\')
lcWorkarea = juststem(lcSource) && You may need to change this line!!
Select (lcWorkarea)
copy to (lcTarget)

NB! Please enable auto quote! Move the mouse pointer to "Message view setup" in the upper right corner of the message area.

>sir, the source dbf in use
>so when i issue your commands then it says
>
>Database z:\c13\tables\acws.dbc: File access denied.
>
>Please help again