I'm also having installation issues-- on a fresh WPMU 3.4.1 install.
I'm getting no error messages on the plugin install--but no options are showing under any of my subsites' Tools > menus in order to actually manage the domains. "Domain mapping" configuration and "Domains" are options under superuser's settings, but that's it. Any domain I enter under superuser > Settings > Domains disappears and does not populate the db table.
Is this a 3.4.1 issue? Supposedly there's nothing in the latest WP update that should cause this plugin to behave differently than in 3.4.
Just to confirm:
--wpmu is installed in my dev domain's root directory. I.e., I installed wpmu to http://mydevsite.com and not a subfolder of that domain (which I know won't work for domain mapping).
--I manually installed the plugin: uploaded sunrise.php to the wp-content folder, updated wp-config.php, and network-activated the plugin.
--I also set the IP in the domain mapping settings and dealt with the wildcard record on the server end, not that that should affect the issues happening.
--I updated the network.
Anyone else having this occur?