This is a somewhat shorter method that uses the built in "make combined data table" command to produce a table containing all the parameters which you can slice and dice as required.
//Opendatatable and make report
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
biv = Bivariate(
Y( :weight ),
X( :height ),
Fit Line( {Line Color( "Red" )} ),
By( :age )
);
rbiv = biv << report;
//Combine parameter estimates in new table
dtparms = rbiv[1][tablebox(4)] << make combined data table;
dtparms << Set Name("Parameter Table");