Chart Controls for .NET Framework : Is not possible to use two different DATASET in a same chart ?

Question

Hi all, I need your help.

I would like to know if you can publish in the unique chart the data extract from two different queries sql.

Is not possible to use two different DATASET in a same chart ?

My error:

X values cannot be data bound to the string object.
Parameter name: xValue

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.ArgumentException: X values cannot be data bound to the string object.
Parameter name: xValue

Thanks in advance.

Chevy

PS: My code in rar file.