When you open and convert a model that was built in ExtendSim 9, the converted ExtendSim 2024 or 10 model is not associated with a file association until it is saved. Data Import Export blocks use the model path name to resolve the relative file path name specifications. Consequently, Data Import Export blocks using relative file path names will not function properly until the newer ExtendSim model has been saved and is associated with its file.
Make sure that you SAVE the new ExtendSim model following its conversion from ExtendSim 9 before running it.