I have a basic installation of JBoss Portal 2.7.1-GA in JBoss AS 4.2.3-GA.
When I "Copy to my Dashboard" a page, the "Samples" page, for example, I can't drag any portlet in the new dashboard page. The start drag icon appears (the black cross), but drag doesn't start.
Drag and Drop only works for "Home" dashboard page.
Same thing appens if I create a new dashboard page.
This is fixed in 2.7 Branch. I believe upgrade of AJAX library was the culprit. I would have to dig through the log to get the diff but you can give it a shot building the binaries from SVN.