I have the same issue.  Clean upgrade from 3.2.2 to 3.3.4.  When I click on the name of the logged in user, I get a blank page.  Haven't figured it out yet.  Anyone else have the same issue?

I did a little digging on this and found out that:

A local copy of DNN (which displays the profile page fine) uses "/ctl/Profile" in the query string.  Querying the db (local dev) there is a record in ModuleControls that has a "ControlKey" value of "Profile".  This is the pointer to the user control that is being called.  A query of my prod database showed that this record was not in the ModuleControls table.  This control does not have a value in ModuleDefId so there was no key refernce issue.  I wrote a quick insert statment and the profile page displays fine now.

I have also noticed that the same issue exists for the "Manage Profile Properties" link under Admin > User Accounts.  I get the same blank page there.  I haven't checked it out yet but this may be a similar issue.  When I figure it out I will post a follow up.

Interesting, though, I checked back through all of the log errors for the upgrade and didn't see anything that would have indicated a potential issue with these controls.  I upgraded from 3.2.2 to 3.3.4

Hope this helps,

Jonathan