Although, this may be of interest: Once the whole process had finished, I had in the folder the source WAVs, the encoded MP3s, and then more mp3s which filenames were of a temp nature (tmp*****.mp3). The desired mp3s were fine, though.

If you give the --nogap option, Lame expects all filenames on its command-line to be input files (as opposed to one input file and one, optional, output file). Especially on Windows, where the file locking semantics are different from those in its Unix homeland, Lame will likely get quite confused if you tell EAC to use the --nogap option.

Peter