Plain page occurs while install 0.7.8 on second sub domain

I register ByetHost free hosting account with 4 sub domains currently, and create a database.

I have install OpenCart v0.7.8 successfully on first sub domain.
http://www.gifts.isgreat.org/

When I plan to install to my second sub domain, for example:
http://www.gift.isgreat.org
the url change to "http://www.gift.isgreat.org/install/index.php"
but return a plain page.
All the steps are same as my first installation. Dont know which part going wrong?
Can I install OpenCart in a server with different sub domains?

P.S.1 The first sub domain with OpenCart still exist when I install on second sub domain.
P.S.2 Create a database only. Can OpenCart share a database between the 2 sub domains?
P.S.3 Upload the files 3 times at 2 different PC, so i dont think it is missing files.

Need you kind advice. TQ

Make sure your config.php is empty and then call http://www.gift.isgreat.org/

If it doesn't work, check the server's error log for your new sub-domain which should some hints about the nature of the error.

As regards sharing the same database between 2 OpenCart installations:  Won't work, it's not designed for this scenario.

Thanks. It's work now. Thank you very much.

I add another database and everything ok.
(Still remain the same config.php)

So every OpenCart installation on different sub domains need an independent database.
It cannot sharing a same database.