Bizhub Pro 6000 - Folding options

Good morning--

Having an issue with my 6000 -- I send a PDF to print as a booklet and the machine tells me that "it is not possible to fold because of finisher limitation" -- the PDF is 8.5x11 and about 30 pages. I have had no problems doing this same print job in the past.

Only thing I can think of is certain features may have been wiped out when the technician came a few weeks ago to work on an unrelated problem and he ended up having to install a new motherboard and harddrive.

Any ideas? Thanks in advance.