Can't Paste onto Whiteboard during Session

I'm using Version 6.1.12 on a PC and everything is working great, except I can't paste an image onto the whiteboard during a session that I am hosting.  If I open the same whiteboard after a session, I am able to paste onto it.  I use screenshots all the time and have never had a problem with it, but when I try it during a session, nothing happens.  What's worse, other participants in the session are able to take a screenshot (Windows-Shift-S) and paste it onto a whiteboard (Ctrl-V) without any problem.  Help!