A: 

Is it possible to point out a SharePoint user by "domain\user" like you do with createApprovalTask.TaskProperties.AssignedTo? Isnt the ID required?

"id;#domain\username"

JMD
The task item is created for the correct user by supplying the AssignedTo property with "domain\user", so it knows who should be getting the email.
frax
+2  A: 

you have to make sharepoint outgoing email settings properly. example is shown in below link

http://sharepoint-amila.blogspot.com/2008/02/outgoin-email-settings.html

if you need to send an email through the c#.net code you can use below method to send emails in custom workflows. SPUtility.SendEmail Method (Microsoft.SharePoint.Utilities)

example is shown in below link http://www.sharepoint-amila.blogspot.com/

+2  A: 

Unfortunately, our mail servers were blocking the emails for some reason. I wasted a good 2 1/2 days searching around for this problem...and it turns out our IT department didn't have their sh*t together.

Thanks everyone.

frax