After doing the Telus 2.1.1 update on the milestone I ran into this issue. I had to follow the steps from the article.
From the phone go to
Settings > Applications > Manage Applications > [menu >Filter – Running] > select Email > Clear data.
This will clear ALL settings for any email account setup (except the Gmail account) and you’ll have to setup the account again.
The application Email (process com.android.email) has stopped unexpectedly – Android Help.