Hi,
SNS Megamenu did not show on nav-bar. Is your issue? Please see screenshot: http://monosnap.com/image/0cJKwqZIdjwEwKd9dA01PfTtyu69M6#
If so, please go to file: app/code/local/Sns/Megamenu/etc/system.xml and edit
<sort_order>205</sort_order>
Because maybe order of SNS Megamenu is coincides with another module you have installed
