Nirav

With description you have placed here it is impossible to understand where is error. "Object reference..." is 90% error usually and sources of bug can be very different.

It looks like you use object does not exist in Professional edition(can't belive in it, but it looks like yes). You should change references in the Visual Studio to the Professional and to recompile it. In this case you should see error in the Visual Studio and can fix it.

Or another way is to Debug your project step-by-step until you find where is the problem. 

Sergey

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