I noticed this before. Sometimes in some browsers with flash camera dialog you won’t be able to press ALLOW button to access camera, microphone. The issue is already exposed over here Can't click allow button in flash on firefox and Adobe is tracking issue about this bug http://bugs.adobe.com/jira/browse/FP-4656.
The purposed solution sometimes works but also not always. The other workaround I wound on web is to set the margin-left and margin-right CSS in flash container like this:
margin-left: 0.5px;
margin-right: auto;
Well now the OS X Lion came out and the damn thing doesn’t work in any browser! I even tried the Facebook profile photo taker which also uses flash for taking photos. Also there you cant press ALLOW button. Same with YouTube video recorder etc…
What to do?
the only solution works for today is adjust “Flash player General settings” for specific domain