if you installed the above it would seem as you have server access, look at all the logs to find the reason for the white page, which is most likely a 500 internal server error.
some reasons could be the wrong version of phpmotion did you upload the php5 files/
did you upload the encrypted files in binary mode?
do you have all the directores set to the correct permissions, 777 or in the case of php-cgi or
not running as an api, then 755, there is a lot of things that could be wrong.
