The report definition is not valid. Details: Data at the root level is invalid,该怎么解决

The report definition is not valid. Details: Data at the root level is invalid
网站原来报表有服务器端报表和客户端的，之前可以运行，后来全部改成客户端报表，在本地调试运行没有问题，但是上传到服务器报错误，之前的客户端报表也报相同的错，网站重新发布了好几次 还是一样 求解。。
Server Error in '/SG' Application.
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The report definition is not valid. Details: Data at the root level is invalid. Line 1, position 1. 
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: Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: The report definition is not valid. Details: Data at the root level is invalid. Line 1, position 1.

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: 


[ReportProcessingException: The report definition is not valid. Details: Data at the root level is invalid. Line 1, position 1.]
  Microsoft.ReportingServices.ReportProcessing.ReportPublishing.Phase1(CatalogItemContext reportContext, Byte[] definition, CreateReportChunk createChunkCallback, CheckSharedDataSource checkDataSourceCallback, String& description, String& language, DataSourceInfoCollection& dataSources, UserLocationFlags& userReferenceLocation, Boolean& hasExternalImages, Boolean& hasHyperlinks) +804
  Microsoft.ReportingServices.ReportProcessing.ReportPublishing.CreateIntermediateFormat(CatalogItemContext reportContext, Byte[] definition, CreateReportChunk createChunkCallback, CheckSharedDataSource checkDataSourceCallback, PublishingErrorContext errorContext, AppDomain compilationTempAppDomain, Boolean generateExpressionHostWithRefusedPermissions, String& description, String& language, ParameterInfoCollection& parameters, DataSourceInfoCollection& dataSources, UserLocationFlags& userReferenceLocation, ArrayList& dataSetsName, Boolean& hasExternalImages, Boolean& hasHyperlinks) +99
  Microsoft.ReportingServices.ReportProcessing.ReportProcessing.CompileReport(CatalogItemContext reportContext, Byte[] reportDefinition, CreateReportChunk createChunkCallback, CheckSharedDataSource checkDataSourceCallback, PublishingErrorContext errorContext, AppDomain compilationTempAppDomain, Boolean generateExpressionHostWithRefusedPermissions, String& reportDescription, String& reportLanguage, ParameterInfoCollection& parameters, DataSourceInfoCollection& dataSources, UserLocationFlags& userReferenceLocation, ArrayList& dataSetsName, Boolean& hasExternalImages, Boolean& hasHyperlinks) +80
  Microsoft.ReportingServices.ReportProcessing.ReportProcessing.CreateIntermediateFormat(CatalogItemContext reportContext, Byte[] reportDefinition, CreateReportChunk createChunkCallback, CheckSharedDataSource checkDataSourceCallback, AppDomain compilationTempAppDomain, Boolean generateExpressionHostWithRefusedPermissions) +328
  Microsoft.Reporting.ReportCompiler.CompileReport(CatalogItemContext context, Byte[] reportDefinition, Boolean generateExpressionHostWithRefusedPermissions, ReportSnapshotBase& snapshot) +166

[DefinitionInvalidException: The definition of the report 'Main Report' is invalid.]
  Microsoft.Reporting.ReportCompiler.CompileReport(CatalogItemContext context, Byte[] reportDefinition, Boolean generateExpressionHostWithRefusedPermissions, ReportSnapshotBase& snapshot) +228
  Microsoft.Reporting.StoredReport.CompileReport() +72
  Microsoft.Reporting.StoredReport.get_Snapshot() +32
  Microsoft.Reporting.StandalonePreviewStore.GetCompiledReport(CatalogItemContext context, Boolean rebuild, ReportSnapshotBase& snapshot) +352