Showing NO DATA when running the report in EXCEL or PDF

[sepusa]

Help required..I created a report with three queries.
Query A, Query B and Query C is the join of Query A and B.
When I run the query A and B to Excel or Pdf it is working fine but when I run the Query C to Excel or Pdf it is showing NO DATA but it works when runs as Html..
Can any one please help me to find and fix the problem.
Thank you so much in advance.

[BigChris]

Have you got any render variables or anything that would mean that your list wasn't displayed when you run your report in excel format?