Rename the f4v extension to flv, insert as flv in dreamweaver, and it will work as normal. If you wish you can then change the extension back to f4v, and it will continue to work.
Adobe Media Encoder, without warning, embeds a huge iSkySoft logo in the upper left hand corner of every movie I put in the queue. I did find a way around it, though. One must specify Flash 9.0 or above to avoid the un-invited logo embed. Absolutely disappointing. I read in a post that the Encoder is a stand alone added to CS4. Dreamweaver will only accept FLV or FL4 files, and the Media Encoder will supply this, but at a hidden cost. Really, all users must download Flash 9.0 to view my videos without the iSkySoft logo?