DNS/MX issues arising when migrating Heroku app to Dream Host hosted domain

view full story

http://serverfault.com – I'm not sure if this question belongs here or elsewhere on StackExchange. Otherwise here goes... I have a domain - myapp.com - hosted by Dream Host. Up until recently I had some php as a signup form at that domain. I also had a one-click install of Word Press at blog.myapp.com, and could log into GMail through Google Apps from Dream Host at mail.myapp.com. A few days ago I migrated my Rails app over to myapp.com using Heroku's Zerigo add-on. Zerigo worked magic migrating my app over to myapp.com, however blog.myapp.com didn't work, and neither did mail.myapp.com. (I could access mail but I (HowTos)