Database Logon Error

Im trying to make a script to export to pdf. It seems to be working OK until it gets to the ExporttoDisk Method. Its saying Database logon failed. Heres the code im using to set the logon details:

VB Code:

crReportDocument.SetDatabaseLogon("username", "pword", "server", "db_name")

The parameters Im using are definately correct, I have no problems using them when running crystal and ODBC drivers. But in VB its failing.

This is where it stops and shows the error:

VB Code:

crReportDocument.ExportToDisk(ExportFormatType.PortableDocFormat, exportFilePath)

Are there any known issues with this function? Is there anything else Im missing? Im pretty sure my login details are right and are working.

Thanks