some contests have different rules... e.g. the diary of the month you can only submit a diary 1 time.
*after a year or more i believe this gets reset, as you can find diaries with multiple wins in contests that have this stipulation. or, maybe it was due to site maintenance and variables get reset, i don't know... but it does happen and not sure if we can predict when it will happen.
so, i'd assume you tried to submit the same diary to november that you submitted to october? that would be why. Also, they have to be finished diaries too.
newbie of month rules you can find at top of contest page:
Newbie/Apprentice status
'First Grow' Diary (first growing experience)
Single strain Diary
Diary with a harvest
Diary with a 'smiley face'
Join this OR 'Diary of the Month'
if you get too many likes, it'll disqualify you. if you join diary of the month you cannot join newbie... if the diary was submitted to oct diary of teh month, it may also make it ineligible for newbie of month in future.. that last one you'd have to test to be sure, but 90% certain.
anyway, don't assume it won;t be eleigible for non-monthly diaries or different contests that pop up. always try no matter what the rules say, just my 2 cents.