Here we are trying to migrate reports from MS CRM 2011 Onprem to MS CRM D365. This will also help you for below error or if you are migrating reports from older version to newer version.
When trying to compile a FetchXML-based report in Visual Studio 2015 which had been developed in an earlier version of Visual Studio, we encountered this error:
Building the ReportName.rdl file for SQL Server 2008 R2, 2012 or 2014 Reporting Services.
[rsErrorLoadingCodeModule] Error while loading code module: ‘Microsoft.Crm.Reporting.RdlHelper, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35’.
Details: Could not load file or assembly ‘Microsoft.Crm.Reporting.RdlHelper, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35’ or one of its dependencies. The system has not found the file specified.
[rsCompilerErrorInExpression] The Language expression for the textrun ‘Table0_Details0.Paragraphs[0].TextRuns[0]’ contains an error: [BC30456] ‘Crm’ is not a member of ‘Microsoft’.