I thought there were two folders because you said you split it into parts to keep the size under 1 GB.
Your file names are not a consistent sequence where each file name has the same number of letters and numbers. The script probably doesn’t like hyphens so remove them.
The first file must be
e001.au
Then e002.au, e003.au through to e600au.
If the recovery tool does not like the “e”, replace it with a “b”.
Gale