>Here is the index key Unassdoc
>
>“DTOC(when_sent)+doctor_last_name” (when_sent is a datetime field) (doctor_last_name is C(35))
>
>And the Filter is “status = 5” for this key
>
>There are NO Memos in this key.
>
>I can go in and Rebuild Indexes, and sometimes this fixes it. Then when I run the code, the error reoccurs.
>
>
>Since there are NO Memors, then why would the error occur.

Don't use DTOC function in the index. Use DTOS() instead. Check DTOC() in Help as to why (you can use it with second parameter).