To start, take a look at this thread that lists a lot of scripted find examples: Scripted Find Examples
You can use "<" & Get ( CurrentDate ) + 30 in the due date field. and "=" as the criteria in the Complete date field to find the records that you have specified as this will find all records where the completed date field is empty and the due date is within 30 days of today.
ok i tried what you said, but keep getting this error "This action cannot be performed because this field is not modifiable."
my script looks like this:
Set Field [Student Info::MSc Proposal Complete; "="]
Set Field [Student Info::c_MSc Proposal due; "<" & Get ( CurrentDate ) + 30]
Sort Records [Restore; No dialog]
in the link you gave i noticed it said i had to have a global field or it wouldn't work?? i dont understand that, but the only global field i have in my entire database is the Academic Year, and it has nothing to do with this report.
You need to enter find mode first. If your script is in browse mode, this won't work and if the set field step refers to a calcuation field (and is not in find mode), you'll get the error that you describe.
Global fields are necessary for any fields used by the user to specify criteria for the search before performing the find. Since there are no user specified criteria in your case, you don't need a global field.