How to pass csv data source as parameter from main report to sub report.

I have to create a multi-page report for this i have created one master page and 7 sub reports. Each subreports uses one csv file as data source. All sub reports are connected to master page too. If i am compiling subreports individually it will work . If i try to compile master page after adding subreports it will generate error. I am totally new to this jasper report. Plz give me some solution to this problem