1) Add the elggdata folder to data.zip BUT delete all files of root folders of that elggdata
2) Take the data.zip after logging in the manual installation.
3) We have disabled auto upgrade in 1.9.1 because it requires datadir upgrade when upgrading from 1.8.x, please check auto upgrade from 1.8.x if you enable auto upgrade in future
4) Add a trailing slash '/' for datadir path in manual installation. (Not required now since 1.12.11)
5) PHP REQUIREMENT LINK: http://learn.elgg.org/en/stable/intro/install.html#requirements