Hi Buddy,
I feel the issue is with 'Subreport links', if the Subreport has parameters either Database parameter or Report Parameter, they should be linked to the parameters of the parent report otherwise the subreport will prompt for values for its parameters.
The Subreport parameters and the parent report parameters should match in Datatype. The Subreport should have equal or less number of parameters compared to that of the parent report.
hope this was useful.
Thanks.