Invalid export DLL or export format

[David Valle]

Hi,
i've follow an example that Gabriele G. Ponti wrote on 8/5/2003 about the export of a report made in Crystal Report in PDF format, this:

------------------------------------------------------------------------
This is how I export reports to PDF files:

Dim diskOpts As New DiskFileDestinationOptions

' load report
m_Report.Load(strReport)

' set data source
m_Report.SetDataSource(dsData)

' initialize the export options
m_Report.ExportOptions.ExportFormatType =
ExportFormatType.PortableDocFormat
m_Report.ExportOptions.ExportDestinationType =
ExportDestinationType.DiskFile

' set destination filename
diskOpts.DiskFileName = strOutput

' set the export options
m_Report.ExportOptions.DestinationOptions = diskOpts

' export the report
m_Report.Export()
-------------------------------------------------------------

it work on my pc. Now i've installed my web application on a server test and when i try to make a report .NET show this error:
"Invalid export DLL or export format"
what i've forgot in my installation?
Thanks to everyone that can help me.
David Valle

P.S.
Sorry for my bad english :)