Why do I get 80040108 errors?

When using CDO, you might see this error: 
 

error '80040108'

 
 
This can happen if you try to read or write a CDONTS property or a CDO configuration property after the mail has been sent. Allegedly, these parameters are destroyed immediately after the message is sent, so they cannot be accessed afterward - yielding the above error (which maps to CdoE_INVALID_OBJECT). 
 
This can also happen if you do something like this: 
 

<%      ' ...      objCdo.body = "foo" & _      objCdo.send  %>

 
If you don't end that string correctly, the CDO object is going to try and append the send method to the body, which of course is going to confuse the heck out of it. :-) So check your code for little items like that... 
 
In addition, if you are using CDONTS.NewMail, consider using CDO.Message instead (see Article #2026).