If you can't find a ZD with FW 9 or higher to have it upgrade the AP there are things you can try. First try changing the FTP server. I think you've got the fwupdate.ruckuswireless.com server there. Change that to fwupdate1.ruckuswireless.com (notice the 1)
If that doesn't work. I'd suggest you download the FW from the RW page, start a TFTP server on your LAN and upgrade it that way. You'll need a control file. I don't know exactly how these look like for ZoneFlex but if you go by how MediaFlex controll file looked like it would be something like below.