For future users who might experience something like this:
I had modified the default members navigation options using bp_core_remove_nav_item(). One of the nav items I removed was messaging. I suppose removing the nav item somehow breaks the whole function. I had encountered a similar problem when I removed the ‘profile’ tab – it broke everything! Does anyone have any comments on ways to remove the nav options without breaking things? As of now, I’m using CSS display:none to hide the profile and messaging tabs.
@henrywright – I am logged in, and what I am trying to do is view my own inbox or compose a new message (not view a pre-existing thread). The permissions thing makes sense, though, maybe I’ll try exploring that road…