i did not overwrite i just uploaded new forum
and before this i uploaded version 4.1.10 and i face same error then i delete every file from server and reupload 4.1.11 patch level2 but still same error
So that file is already from the new package then? In that case ignore the error message and run the upgrader. But make sure to make a backup of your database first.
P.s. Is this a new install btw or are you upgrading your forum?