This File/Folder exists but its permissions may not be modified automatically, please apply CHMOD manually and then click on "Start Install Anyway".
well, that's ok, but if i set the permissions, it tell me the following:
Unknown error while checking this File/Folder. Please make sure that this File/Folder exists on the server, that it has the correct CHMOD permissions and then click on "Start Install Anyway".
I don't know what it's happenig.¿what is wrong?.

Thanks.