Only thing i would suggest is to file a ticket to phoenix/firestorm support. are you using the latest version of phoenix? if so maybe go back to previous version.
I updated to the latest Phoenix viewer and take lots of photos with no problem. Are you using shortcuts or the menus? The shortcuts may be the problem.
I'm not using shortcuts, just the snapshot button witch is located in the "lower" menu.
and the version of phoenix I'm using now is 126.96.36.1995