some plugin or other on the homepage is blocked on my version of FF 3.6.13 and in IE6 and FF it is invoking a warning about external app - probably Windows Media Player.

This may be because the web designer has all the best gear - and your audience don't! It may be because I am running FF portable on a proxy server (& remote instance of XP) but IE is the same.

I keep my website old fashioned for this very reason - the data are king, gizmos aren't. Your website has to function and look good because the psychology of these things is good looking appears trustworthy. So no problems on that front. Though looking good is not how I judge these things (consciously anyway).