Reusing the variable 'str' here for multiple purposes meant the QWK packet
filename was overwritten by the owner name (the system's BBS-ID):

 ftp> mlsd
 229 Entering Extended Passive Mode (|||2001|)
 150 Opening ASCII mode data connection for MLSD.
 Type=file;Perm=r;UNIX.ownername=VERT; 00index
 Type=cdir;Perm=elc;UNIX.ownername=VERT; /
 Type=file;Perm=r;UNIX.ownername=VERT; VERT

That last file there should have been "VERT.qwk"