>>Note: the name of the field is almost 50 characters. Does this have anything to do with the problem?
>
>Don't know for sure, but I think this is a good bet. Why on Earth do you have a 50 character field name? This is within the limits of the VFPs spec, but might be over the limits as far as controlsource fields.

This application concerns analysis of the use of pharmaceuticals so the field names are long. e.g. ativan_lorazepam_halfmg_routine.

I'll try shortening the names.

Thanks,

Alan