Crystal subreports & VB

Hi Everyone!
I have some reports I'm calling to from VB. These reports have two subreports each.
An error ocurr when I try to open it from my application. But when I run it step by step and I put the report object into inspection, there's no error (if I run it step by step by I don't inspect the object, I get the same error)
Sometimes it showed me a TSLV error.
If I take subreports out, I can see the report.
If I run the report (with subreports) from Crystal, I have no problem.
I don't know what happens.
Does anyone have an idea?