Mike, I found the same problem. I wonder if a reference to a field that was deleted from the script at some point in time is still be stored somewhere in FileMaker.
Solutions converted from FM6 or earlier often contain a script step "Goto Field " instead of "Commmit Records", where indeed the field argument is missing. This is no real error, just old syntax.
I have seen this in HTML DDRs from 11 where a script step has an option for specifying a field but it is not actually required, but the DDR still reports an unspecified field option as <missing>. I've not interpreted it as corruption, nor had any problems from this type of option being unspecified.
If you get this warning when a field really should be specified, it's worth updating the script(s) and then outputting a new DDR to check that all is then OK.
The most likely explanation is one of two things : It's a field missing in a sort script step, or a deleted field from a calculation that isn't being used.
In sorts, the DDR will correctly report that the field is missing if you delete a field that is in use in the sort step. But the UI for sorting has no mechanism for displaying a missing field, so you would never know by looking at it. If you open the sort details, ok it, and save the script without altering anything it will actually remove the missing field and all will be well. ( Except for the fact that you originally wanted to sort by a field that isn't there.)
For calculations, try this : Create a calc field with some calculation body in it. Save and close the Define dialog. Open it again and change it to a normal text field, then run the DDR. If you have a look, the field has kept the calculation definition. You can safely delete any fields used in the calc and it won't alert you, and you'll get a field missing in the non-used calc. The same occurs in script steps with calculations.
Are you able to tell from the DDR what sort of step it is? If not, import the xml DDR into BaseElements, as it distinguishes between false errors and real ones and will tell you if there's a legitimate issue to be concerned about.
if you try to delete a field used in a Script Step, FileMaker will at least warn you
however, any other calculated data, or LookUp, or Validation that is no longer "checked" off is still there in the background
If you ever find what's "missing", please report it as a Bug
> But the UI for sorting has no mechanism for displaying a missing field, so you would never know by looking at it
It for have a show dialog step and use 1 or 2 fields for data entry, you will get the "missing file". If you use all three fields or none of the fields, you will not get the "missing field".