"No section" with commond "miniccnx --testbed"

hello
i have install quagga and ospfn on my VM successfully , while when i change to the sopfn/ directory and issue the commond "miniccnx --testbed", the terminal show "No section" error ,(i.e. "ConfigParser.NoSectionError: No section: 'preferences'") , while in the install section , i've got a same problem with this error , and at that time i follow your suggestion and modify the file miniccnx.conf add [preferences](and it's related detail) and so on , it works, while this time ,did i have to do the same work to solve the problem?but it's in ospfn ! how can i solve the problem?

maybe it's not a good research behavior, but when i copy the miniccnx.conf from mn-ccnx/ directory to the ospfn/ directory , the commond miniccnx --testbed it works ! while i konw the default minccnx.conf was really different from this one , the old one containes many other argument , while i just recover them, the --testbed commond works , do you know why ? why it will work ?