Hello

I have a wordpress website. Recently i checked my Google webmaster and saw increase in structures data errors of these kinds:

Data Type: Hatom Source: markup: microformats.org Items With Error:1608

Further opening it i saw:

Error Type: Missing Update and Missing Author on 4 pages of website.

I have author visible on each post with date too.

How to solve these errors??? Are these errors harmful for my website???

Thanks
Mani Kunis