Filippo, Your issue is that you are not specifying which fields are to go to the DataGrid. By using:<fields all="true" />
you are missing the fact that each field that you want to send to the datagrid has to have a gridfield or gridfieldonly attribute.Here is a typical field xml portion that specifies which field do send to the datagrid: <fields all="false">
<field name="PPIN" gridfield="true" alias="Parcel Identifcation Number"/>
<field name="NAME" gridfield="true" sort="asc|1|string"/>
<field name="STREET_ADDRESS" gridfield="true" />
<field name="USE_CODE" gridfield="true" />
<field name="CALC_ACRES" gridfield="true" />
<field name="EXEMPTION_CODE1" gridfield="true" />
<field name="ADDRESS_1" gridfield="true" gridfieldonly="true" />
<field name="ADDRESS_3" gridfield="true" gridfieldonly="true" />
<field name="PRIOR_TAX_YEAR" gridfield="true" />
<field name="SALE_DATE" gridfield="true" dateformat="MM/DD/YYYY" useutc="true"/>
<field name="LAST_DEED_BOOK" gridfield="true"/>
<field name="LAST_DEED_PAGE" gridfield="true"/>
<field name="ZIPCODE_1" gridfield="true" gridfieldonly="true"/>
<field name="NEIGHBORHOOD" gridfield="true" gridfieldonly="true"/>
<field name="SUBDIVISION" gridfield="true"/>
<field name="SALE_PRICE" gridfield="true" currencyformat="$|2|,|." sum="true" sumlabel="Sales Price: "/>
<field name="TOTAL_TRUE" gridfield="true" currencyformat="$|2|,|." sort="dsc|2|numeric"/>
<field name="LAND_PRICE" gridfield="true" currencyformat="$|2|,|." />
<field name="IMPR_PRICE" gridfield="true" currencyformat="$|2|,|." />
<field name="ADJ_PRICE" gridfield="true" currencyformat="$|2|,|." />
<field name="OVER_COND" gridfield="true"/>
</fields>