I had several reports written on SSRS 2000. When I added SSRS 2005 and SSRS 2008, I uses VS 2005 and VS 2008 to upgrade copies of all the reports, respecitively. The copies all work in each version, except for one line chart report (The rest are mostly tables). The line chart works fine in RS 2000 and RS 2005, but I get an error in RS 2008.

The database query works OK. Everything looks "normal" in design mode, but when I go to preview mode, I get the following message:

An error occurred during local report processing.

An error has occurred during report processing.

The processing of Parent for the chart 'xxx' cannot be performed. The comparison failed. Please check the data type returned by the Parent. (Name of chart changed for security reasons)

There are three data fields plotted, all integers.

There are three category fields, two integers and a string.

There are two input parameters, both dates.

The two date parameters are passed to a stored procedure, which generates a table, with the results to be plotted.

I'm assuming there are some backward compatibility issues I'm not aware of.