insert flash video error

When trying to insert .flv file into my page in Dreamweaver CS3, I get the
error:

While executing onClick in FlashVideo.htm, the following javaScript error(s)
occurred:
At line 621 of file "C:\Program Files\Adobe\Adobe Dreamweaver
CS3\Configurations\Commands\FlashVideo.js":
setSelectedNode: Argument number 1 is invalid.

In FlashVideo.js, line 621 reads:
dom.setSelectedNode(selNode, false, true);

Can anyone help?