One final note:
JFreeReport contains two CSV output targets. Number one is the Data-CSV target. It fully ignores the report definition and exports the datarow and some status information. Due to its fixed format it is not suitable for general use - but can be useful if you need to postprocess the computed report data.
The second, more complicated output target uses the table-exporter to produce a CSV file. This mode is called "table-CSV", and depends on the layout of the report definition. If the report definition is crafted carefully, this one can be very useful, but to the novice user this may be the equivalent of 'shoting yourself in the foot'.
This is also the reason why there are two separator config-properties. The one you used initially was for the data-CSV, but aparently you used the table-CSV. And that one uses an other config-property (the one that was given in ulrich's posting).