par2cmdline apparently doesn't bother checking errno
when creating large numbers of files, and thus just
complains that it can't open a file. Were it to check,
it would find EMFILE, which is a good indicator that it
should find a way to do what it's doing without so many
files being open at once. As far as I am aware, the
interleaving of R-S erasure codes should allow for
multiple passes to be made, one per "set" of recovery
blocks.