Hi Rahul,
Thanks for your interest in Syncfusion Products.
This is due to the usage of dll for a different framework. You need to set the framework of the project correctly in order to make it work. If you are using framework 2.0, you need to set the framework by the following Steps:
1) Right-click on project and choose properties.
2)Choose Application from left tab.
3)Choose Target Framework as 2.0.
Now, you could refer your dll "4.402.0.51" in your project, and now it should refer correctly.
Please let me know if you have any concerns.
Regards,
Athiram S