Not sure why, maybe the difference in computers, or ISP providers, but Opera browser was awful for my husband and I.
Firefox had glowing recommendations from several CC-ers but for me it eventually freezes CC and the mic is in and out. I used Torch successfully for awhile, but it is no longer supported.
Some folks seem to do fine with Chrome, others hate it. Go figure.
IE is the only browser that totally works for me. I think I am in the minority however because I hear so many people that have problems with IE.
My suggestion to the original poster, is to just keep trying a different browser until one of them works.