Server Error in `/` Application.

Server Error in '/' Application.
Conversion from type 'DBNull' to type 'String' is not valid.
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.InvalidCastException: Conversion from type 'DBNull' to type 'String' is not valid.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information
regarding the origin and location of the exception can be identified using the exception stack trace
below.
Stack Trace:
[InvalidCastException: Conversion from type 'DBNull' to type 'String' is not valid.]
Microsoft.VisualBasic.CompilerServices.Conversions.ToString(Object Value) +1073
eRef.PdfGenerator.Web.partnumber_eShop_v3.PartnumberTechnicalInfo(Int32 _SalesOrgId, String _ProductId, Int32 _LanguageCode) +5
eRef.PdfGenerator.Web.partnumber_eShop_v3.Page_Load(Object sender, EventArgs e) +972
System.Web.UI.Control.LoadRecursive() +116
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2750
[TAG[PDFDisclaimer]]
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1031
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