This may have more to do with the joins and the selection criteria than with this particular formula.
I would try taking the group out and see whether there is any data returning for your report. If there's not, then you need to look at two things:
1. Joins: I would start with a new report (so you don't lose what you've done on the existing one!) and add the first two tables with their joins. DO NOT do anything with adding selection criteria yet. Verify that you have data. Add another table with its join(s). Verify data. Keep doing this until you have all of the tables and joins. At some point in the process you may not see any data because one of the joins is set as an inner join when it needs to be an outer join.
2. Selection Criteria: If you get all the way through step 1, start adding the selection criteria one field at a time. If at some point you don't have any data, you'll need to look at the condition that was just added. Frequently I see issues with tables that have been outer joined but that have selection criteria applied. For example, if I'm outer joined from Table1 to Table2 on Field1 in each table, but I have a condition on Field 2 of Table2, I also need to check for null values in Table2. This means you have to actually manually edit the formula in the Select Expert so that it looks something like this:
...and
(IsNull({Table2.Field1}) or {Table2.Field2} = "Blah")
Note the parentheses and the fact that the null check comes BEFORE the value check. These are required in order for this to work correctly.
-Dell