Why would I not be allowed to answer? My reputation is 101. Is it because the reputation count includes 100 bonus reputation?
Read this page:
It says here:
Note that one needs to earn 10 rep on the site to be able to answer a protected question. The association bonus does not count.
You need to earn 10 rep on the site, and not get it through bonuses. This means that you need to get upvotes or edit posts.
Otherwise, you cannot anwers protected questions.