Calculating the reactions at points C and E is essential for constructing shear and moment diagrams. The discussion highlights that the reaction at C is zero, which raises concerns about the beam's equilibrium. The reaction at E is determined to be 2.43 kN based on the sum of moments. However, without a reaction at C, the beam cannot be in equilibrium due to a net moment around C. Properly assessing all reactions is crucial for accurate analysis in statics problems.