SSRS - Cannot create a connection to Oracle data source Error

Hi,

From time to time some of the ssrs reports connecting to oracle data sources gives "ORA-12154: TNS:could not resolve the connect identifier specified" error. Restarting IIS fixes the issue. This happens only with data sources connecting to Oracle databases. Below is a transcript of the error message from reportserver logfile.

Any help would be much appreciated.

Thanks,

Joseph.

w3wp!processing!6!31/05/2010-10:45:02:: e ERROR: Data source 'ds_: An error has occurred. Details: Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: Cannot create a connection to data source 'ds_. ---> System.Data.OracleClient.OracleException: ORA-12154: TNS:could not resolve the connect identifier specified

w3wp!processing!6!31/05/2010-10:45:02:: e ERROR: An exception has occurred in data source 'ds_. Details: Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: Cannot create a connection to data source 'ds_. ---> System.Data.OracleClient.OracleException: ORA-12154: TNS:could not resolve the connect identifier specified

w3wp!processing!6!31/05/2010-10:45:02:: i INFO: Merge abort handler called. Aborting data sources ... w3wp!processing!6!31/05/2010-10:45:02:: e ERROR: Throwing Microsoft.ReportingServices.ReportProcessing.ProcessingAbortedException: An error has occurred during report processing., ; Info: Microsoft.ReportingServices.ReportProcessing.ProcessingAbortedException: An error has occurred during report processing. ---> Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: Cannot create a connection to data source 'ds_. ---> System.Data.OracleClient.OracleException: ORA-12154: TNS:could not resolve the connect identifier specified