Did you ever resolve this issue? I'm facing the same problem. I am using version 2008.1 but I can upgrade to 2008.3.
Ken,
Likely this has been addressed in the latest hotfix as mentioned then. I can't really do anything from here, but Developer Support should be able to verify if it has already been fixed, or what version it was fixed in.
-Matt
I can reproduce it everytime with the exact settings from above. It is very annoying.
-Ken
Even when I set the newer AutoCompleteMode property, or the obsolete AutoComplete property, I didn't get an exception when there was a row having null values for both the DisplayMember and ValueMember. You should submit a small sample to Developer Support, or also ensure you have the latest hotfix, as mentioned previously.
Set AutotComplete property to "True" to be able to reproduce the issue