Report Builder - Error!

I defined a report through the Development Studio of SQL server 2005 which has got a grid and a chart in its layout. If i try opening the same report through the Report builder I get the following error. Why is it so?

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Cannot open this item
The report cannot be opened in the report builder.
Object reference not set to an instance of an object.
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And also, by default the Report Builder provides the layout of Matrix, grid and Chart. Does that mean that I cannot define reports having the mixed element like a chart and a grid in one single report?

-- Muthu

Report Builder does not generally support opening arbitrary reports created in SQL BI Development Studio, although you may get lucky occasionally. No, in this release Report Builder does not support multiple data regions in the same report.