Can´t save my web player project as index.html

When i save my project in a index folder, there appears an error: Error building Player: IOException: Failed to Move File / Directory from 'Temp/BuildingWebplayerTemplate\index.html' to 'Temp/BuildingWebplayerTemplate\index.html'. It works perfectly fine when i save it elsewhere... I want it to be index.html Couse then the homesite will have it as a main page. Thanks in beforehand :)!