1.       The Elevation TIM or DEM you were using seemed problematic based on the Arc Map Error message (I searched the ESRI database and could not see any easy remedy)
2.      You can make a Contour from the Rim Elevations of your InfoSWMM model
3.      The contours will cover the outline of the nodes and junctions
4.      Convert the Contour to a DEM using the Arc Map Toolbox or the InfoSWMM Subcatchment Manger Convert Tools
5.      Use InfoSWMM Ram to create a flood map
6.      Use the Created DEM (Elevation1) and use the option Based on Maximum Head
7.      A Flood Map shape file will be created
8.     It will overlay the node and link layers of InfoSWMM
9.      The bullet points in this list correspond to the Bullet points in Figure 1

Figure 1:  Using InfoSWMM Risk Assessment Manager