For those who still need help with the issue of "You are not allowed to create or update this content":
I just ran across this yesterday when I was trying to post a question to Apple Communities for the first time. (I know you figured out how to post but maybe this will help someone else...) After searching the community, I tried several things:
1) Shortened my topic title (i.e "Post. Tell us what is on your mind.") to only a few words.
2) Shortened the explanation/summary of the question to a few sentences.
3) As part of 2) I took out the part of the question asking about third-party software (wondered if referencing this in the question wasn't allowed?)
4) Selected a different community than I had on my first attempt (chose Safari instead of iPhone or iPad)
5) Added the product (iPad Air) to my profile even though it isn't registered under my Apple ID (it's under her father's).
Not sure which of these did it, but I was able to post my question just a bit ago.
MIght help help if Apple would place tips/helpful hints by each section (Post. Summary of your question. Community. Product.) to help us newbies figure out where we are getting stuck. (BTW: Anyone know how I send them that suggestion? Do they read the ASC posts?)