Return Service Label generation failed for UPS.

Hi,
I am getting following error when generating UPS return label using Shiprush 10.2 version.

First time its creating label correctly but when i am trying to create shipment and execute method StartNewShipment(), it is giving this error.

Return Service Label generation failed for UPS.
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Assertion failure (S:\Develop\components\production\shipping\UpsBold \ActiveX\ActiveX_UPSShippingForm.pas, line 2217)

Thank you,
Rahul.