Crystal reports

[Bonj]

Hi
I am trying to create a simple 'hello world' type web application involving
a crystal report.
I have basically done it the simplest possible way as described in the
documentation, by adding a crystal report, choosing the data source for it*,
and selecting columns.
I then added a CrystalReportViewer from the 'Web forms' tab to the
WebForm1.aspx page, and then also added a ReportDocument thing from the
components tab (with the 'cached' check box ticked), and selected the
crystal report I had added from the drop down. In the databindings property
for the CrystalReportViewer, I chose the ReportSource from the bindable
properties listbox, and chose the ReportDocument component I had added.
Now - in design mode - I have got it to display the report's columns
correctly. But when I hit F5 to test the project, or navigate to its web
location in internet explorer once compiled, I get the exception as listed
below.

*I thought it might be due to the database connection, but I have tried it
with SQL server authentication and integrated security, and it does the same
thing whatever. When designing the crystal report, I logged on to the
database successfully and was able to choose its columns and that. How come
it's OK in design mode, but when I run it it won't logon correctly? What am
I doing wrong? I have followed the instructions in help to the letter.

Any help much appreciated!

Logon failed.
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: CrystalDecisions.CrystalReports.Engine.LogOnExcept ion:
Logon failed.

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:

[LogOnException: Logon failed.]
.K(String 
, EngineExceptionErrorID )
.F(Int16 , Int32 )
.E(Int16 
)

CrystalDecisions.CrystalReports.Engine.FormatEngin e.GetPage(PageRequestConte
xt reqContext)

CrystalDecisions.ReportSource.LocalReportSourceBas e.GetPage(PageRequestConte
xt pageReqContext)
CrystalDecisions.Web.ReportAgent.v(Boolean `)
CrystalDecisions.Web.CrystalReportViewer.OnPreRend er(EventArgs e)
System.Web.UI.Control.PreRenderRecursiveInternal()
System.Web.UI.Control.PreRenderRecursiveInternal()
System.Web.UI.Control.PreRenderRecursiveInternal()
System.Web.UI.Page.ProcessRequestMain()