It looks like the person who made the EBIT workflow originally had the PublishToTableauServer macro installed in different directory from yours, so the reference in the file points to the wrong location.
You should be able to fix the workflow like this.
Warning: This technique involves directly editing the xml in the .yxmd. Make sure you have a backup of the file before attempting this
Part 1. Find the correct paths for the macro location on your computer
1. Create a new workflow called MacroLocation.yxmd
2. Drop the PublishToTableauServer onto the canvas
3. Save the workflow
4. Open this workflow with a text editor. I use Notepad++ but Notepad.exe will work fine.
5. Search for the following line.
This should find the xml node that refers to the Publish macro
6. Within this node, find the EngineSettings element. It's probably the last element in the node. Mine looks like this.
<EngineSettings Macro="PublishToTableauServer_v2.0.0\Supporting_Macros\PublishToTableauServer.yxmc" EngineDll="Macro" EngineDllEntryPoint="PublishToTableauServer_v2.0.0\Supporting_Macros\PublishToTableauServer.yxmc" />
Yours will probably have a different Macro and EngineDLLEntryPoint
5. Copy this entire line including the opening "<" and closing "/>"
Part 2. Find the reference in the broken file
1. Make a copy of 20190509_EBIT_V11.5_FZI_DEV.yxmd
2. Open the copy with a text editor.
3. Find the EngineSettings element for the Publish macro using steps 3 and 4 from part 1
4. Replace this entire line with the copy you made in part 1
5. Save the file copy
6. Open the file copy in Designer
This should fix your problem. If it does, rename the copy to something official sounding and use it from now on. If not, post the results here.