You're not alone! A quick trip to the Blogger Help Group shows that MANY people are still having trouble commenting on the posts of others. Normally, problems like this are fixed within a day or so of Blogger hearing about them. Not this time!
Fortunately, there are a few bloggers out there who have worked hard to come up with a temporary solution to this frustrating problem. If you're having comment woes, check out this post. Hope it helps! :)