Reporting Services 中的 PDF 导出问题

PDF Export issue in Reporting Services

在 Reporting Services 2008 中将报表导出为 PDF 时遇到错误。

错误信息是；

Object reference not set to an
instance of an object. 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.Exception:
Object reference not set to an
instance of an object.

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:

[Exception: Object reference not set
to an instance of an object.]

[Exception: An error occurred during
rendering of the report.]

[Exception: An error occurred during
rendering of the report.]
Microsoft.Reporting.WebForms.ServerReport.ServerUrlRequest(Boolean
isAbortable, String url, Stream
outputStream, String& mimeType,
String& fileNameExtension) +520
Microsoft.Reporting.WebForms.ServerReport.InternalRender(Boolean
isAbortable, String format, String
deviceInfo, NameValueCollection
urlAccessParameters, Stream
reportStream, String& mimeType,
String& fileNameExtension) +963
Microsoft.Reporting.WebForms.ServerReport.Render(String
format, String deviceInfo,
NameValueCollection
urlAccessParameters, Stream
reportStream, String& mimeType,
String& fileNameExtension) +28
Microsoft.Reporting.WebForms.ServerModeSession.RenderReport(String
format, Boolean
allowInternalRenderers, String
deviceInfo, NameValueCollection
additionalParams, Boolean
cacheSecondaryStreamsForHtml, String&
mimeType, String& fileExtension) +85
Microsoft.Reporting.WebForms.ExportOperation.PerformOperation(NameValueCollection
urlQuery, HttpResponse response) +150
Microsoft.Reporting.WebForms.HttpHandler.ProcessRequest(HttpContext
context) +183
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
+181 System.Web.HttpApplication.ExecuteStep(IExecutionStep
step, Boolean& completedSynchronously)
+75

但是，此错误并不总是出现在此报告中，它仅发生过几次，具体取决于我们在报告参数中使用的日期。我是 Reporting Services 的新手，任何人都可以帮我找出可能导致问题的原因吗？