Hi Al and Egon,
Some Simulink blocks implement portions of their functionality using shared libraries (DLL files on Windows). Additionally, in some cases EXEs generated from models using these blocks are dependent on these shared libraries as well. In this case it seems like the Simulink UDP Send block has some of these dependencies.
The PACKNGO function can be used to locate the needed shared libraries. Go into your modelname_target_rtw folder and load the 'buildInfo' object into the workspace from the "buildInfo.mat" file. Then you can execute the command
This will create compressed folder in the same directory containing the generated EXE. This compressed folder should contain any DLLs that the generated EXE is dependent on. When running the EXE outside of the MATLAB/Simulink environment these DLLs need to be on the system path or within the same directory as the EXE.