I was looking at the Wikipedia entry for EA and found this chart which does a great job showing the differences of ENTERPRISE Architecture vs. SOLUTION Architecture across several categories. This really gets at the heart of a misconception many people have about what EA is and where it sits in the grand business –> technical detail continuum.
The following image from the 2006 FEA Practice Guidance of US OMB sheds light on the relationship between enterprise architecture and segment(BPR) or Solution architectures. (From this figure and a bit of thinking[which?] one can see that software architecture is truly a solution architecture discipline, for example.)