Could you expand on what you describe for the engine?
epo5301eng - Folder for engine
The engine package MID is expecting, is a package called engmin.zip (for 32-bit) systems.
That is the name of the folder/zip file where the engmin.zip has been extracted to.
I'm pretty sure you need to point to the actual engmin.zip, not an extracted folder.
The latest dats aren't compatible with some earlier engines, so what I think is happening is that there is a mismatch between the engine and dat and fails to install the dat files.
Any reason why you aren't using the 5400 engine anyway? (http://download.nai.com/products/licensed/superdat/engine/intel/5400/epo5400eng. zip ) Extract into a directory and then point to that directory containing engmin.zip/engmin64.zip,
Don't mess with 5301 - very painful as it isn't really a complete engine (just an incremental) - and this could also be part of your issue as well.
If you want to use the 5300 series engine, then point the directory to one containing the zip file for the 5300 engine (as discussed earlier - it must contain engmin.zip/engmin64.zip).