Well... I got the error I pasted in to the message above when I installed the newest version of iFrame. I uninstalled and re-installed the ver 03.02.00 module package that came with DNN 3.3.7 release and now it works again.
I've taken the site live now, so I don't want to muck with it much more. If I get a chance, I'll try ot debug it a bit more and let you know.
However, this error is related to iFrame 3.2.3 as it was the only thing that changed on the site. Maybe the install did not work properly? Maybe it's because this is a DNN install that has been upgraded several times though DNN 3.x versions.
Just thought everyone would like to know.
GregC