Multiple Repeat Articles and Reassigned Authors

I’m not sure if this is in the right spot, but when I imported my site from .com to .org, a lot of my articles either got reassigned to one specific author or were duplicated? I don’t know if it was a direct duplication since some articles are posted twice, and each have different comments attached to them. I’m not sure what went wrong in the process, but can someone help me out?

The site is http://nerdophiles.com