Selecting Columns dynamically in report studio

[saumil287]

Hi all,
I am having a list containing columns as Mach name_Planned, Mach name_Actual,Products and other facts such as Tot pwr consumption_Actual, Tot_pwr_Planned.
I am having a checkbox group which contains multiple column names which is given.
On clicking a part column, adds the column to list.
I am able to do for column containing varchar as datatypes
but not able to do for fact columns
I used the foll link to achieve the same.

http://www.ibm.com/developerworks/data/library/cognos/reporting/dynamic_report_design/page570.html?ca=drs-

Inplace of varchar , I used float, float64 but giving an error .

Your guidance is appreciated.
thanks