Deref and the dreaded yellow triangle!

[ten4info]

Setup deref and it is working, but I am getting the yellow warning triangle along with the value return.  There are a number of records in the lookup table that do not have a Contact value and where there are duplicates of the Company Name.  BUT, there are not actual Contact duplicates (other than blanks where I do not have an actual Contact value inputted).  Help!

And thank you!