I'm not sure if this is the same issue as - http://communities.vmware.com/thread/212853?tstart=30 but I'm getting something similar. Every morning when I log into the VC I get the popup error attached below. All I do is go and enable the plugin and seems like all is well, until the next morning when I login I have to do it all over again. I'm not sure why there would be any database network issues as its running on the same SQL server as the VCDB.
It installed correctly, I'm using SQL Auth, I've used UM to patch all my servers, it seems to be working correctly besides this issue.