bob,
You see that when you install MyEclipse ontop of Eclipse 3.3 for J2EE Developers (Eclipse + WTP). It’s just a notice from the J2EE Perspective that belongs to WTP, that it’s not compatible with MyEclipse.
We usually suggest folks grab the All in One installer to avoid this, or do an Eclipse 3.3 SDK + the PLugin installer or the Manual install.