It turns out the issue is the same as those reporting that the dialog disappears immediately for them. There is a bug in the Facebook SDK in regards to handling error -999, with the solution described in this comment on SO.
I finally realized I was having the same issue (albeit manifesting slightly differently), when I started listening to the FBDialogDelegate's method:
- (void)dialog:(FBDialog*)dialog didFailWithError:(NSError *)errorThe error description referenced the -999 error mentioned above, leading me to the answer. Luckily the code checked into github worked flawlessly. I just had to pull it into the SDK codebase and recompile the .a lib file, then include it into my project.
