As reported by Kat:
The currently selected E-Mail component is not being shown as selected when you go back into EMail Configuration under Admin Options.
change line #192 in admin_config_email.asp:
from:
<option value="<% =theComponentValue(i) %>"<% if (lcase(strMailMode)="'" & theComponentValue(i) & "'" or lcase(MailMode)="'" & theComponentValue(i) & "'") then Response.Write(" selected") %>><% =theComponentName(i) %></option>
to:
<option value="<% =theComponentValue(i) %>"<% if (lcase(strMailMode)=theComponentValue(i) or lcase(MailMode)=theComponentValue(i)) then Response.Write(" selected") %>><% =theComponentName(i) %></option>