Error after deployment

I have a asp.net project. it is ok when in desgined time, but if I deploy it to a deployment project, it is ok for general web form, but if fail with loocal report:

An error occurred during local report processing.
The definition of the report 'Main Report' is invalid.
The report definition is not valid. Details: Data at the root level is invalid. Line 1, position 1.

I must copy all the .rdl file to the deployment folder. But I think it is not the way which deployment projet do.

How can I do