Cognos 10 Validation Error

[Kalyan cognoise]

Hi,
We have migrated Cognos 8.2 report to Cognos 10. Report is running fine but When I tried to validate am getting this below error.
We are using one conditional layout in the report, if we remove that conditional layout report is getting validated.

Variable condition which we are using for Conditional layout: ReportOutput()'PDF' and ReportOutput()'HTML' and ReportOutput()'HTMLFragment'

If yes, we are displaying PDF page else CSV page

RSV-SRV-0042

Trace back:

RSReportService.cpp(856): RSNoFormatException: CCL_CAUGHT: RSReportService::process()
RSReportServiceMethod.cpp(259): RSNoFormatException: CCL_RETHROW: RSReportServiceMethod::process(): validateValidateSpecification_Request
RSASyncExecutionThread.cpp(789): RSNoFormatException: RSASyncExecutionThread::checkException
RSASyncExecutionThread.cpp(250): RSNoFormatException: CCL_CAUGHT: RSASyncExecutionThread::runImpl(): validateValidateSpecification_Request
RSASyncExecutionThread.cpp(842): RSNoFormatException: CCL_RETHROW: RSASyncExecutionThread::processCommand(): validateValidateSpecification_Request
ExecutionContextImpl/RSReportValidateExecutionContext.cpp(123): RSNoFormatException: CCL_RETHROW: RSReportValidateExecutionContext::run()
RSExpressionI.cpp(72): RSNoFormatException: CCL_RETHROW: RSExpressionI::isExpressionStatic()

Please help on this issue..

Thanks in advance,
Kalyan