SWMM 5 GUI Compile Options
These are the Delphi 7 options that should be used to prevent the integer overflow problem from occurring when using the Zoom command. Overflow checking and any Debugging options seem to be the cause of the integer overflow problem.
SWMM 5 after v10 needs an Orpheus component. Here is where you tie in the Orpheus component to the SWMM GUI: