Sorry for the delay. To resolve your issue, please refer the below forum (this works for .net frame work 4.0 and above).
If still the issue is not resolved. Please let us know the exact version of QTP. Are you using QTP 11.0 or UFT 11.50?
Please let us know if you have any concerns.
Thank you for your update.
We couldn’t able to reproduce this issue. Please ensure the following things in your QTP machine.
1. Check whether you have configured the swfconfig file. Please refer the following for reference.
2. Ensure GAC contains all the Syncfusion dlls.
3. Ensure the application build is also .NET frame work 4.5
If still the issue persist, we request you to create the DT incident from the following link.
Please let us know if you have any other concerns.