After trying the home/power button combo about a dozen times and each time coming up the the "iTunes could not connect to this iPhone. The value it missing." message, I did one thing different and it worked.
With my iPhone connected to my computer I did the reset until the iTunes logo came up, in iTunes it gave me two options in an alert/dialog box, if I wanted to "Update" or "Restore", I clicked restore. Then in another alert/dialog box it would ask me "Are you sure?" kind of thing. The first dozen times I continued, and it would do nothing. The last time however I clicked "Cancel" and then then clicked the Restore option that was in the iTunes application window. It then asked me again "Are you sure?" This time I clicked "Restore" (or whatever, not exactly sure, but I confirmed), and viola! it did it's thing!
Hope this helps.