If your subreport have to be at the beginning of the report before your detail data, then putting them in the Report Footer won't work. Here's what I've done for this type of thing:
1. Create a group that applies to the whole report - that is, there is only one time that group will occur on the report. For example, for reports run from our batch system we have a JobID field. Each report contains only one JobID, so I can group on that. Make this Group 1.
2. Create multiple Group 1 header sections, one for each subreport.
If there's no data you can group on for a single group in the report, create a formula called Group1, the formula contains only the number 1. Group on this formula for Group 1.
-Dell