[denobis]

Not implemented in hashswf

if (i->first)
{
i->first = 0;

/* compressed? */

if (!strncmp(p, "CWS", 3))
{
*p = 'F';
i->zlib = 1;
}

HMAC_crunch(i->ctx, (unsigned char *)p, 8);
p += 8;
len -= 8;
i->size = 8;
}

So the program fails when the swf is ZWS which it's managed as FWS