Output to Excel fails

We have a Cognos 8 report that suddenly started to fail. When output to HTML, it works fine. When output to Excel it fails. This report is scheduled and has the output set to Excel 2007. It fails for any output except HTML. The report itself hasn’t changed. We also have a copy of the report in another folder that also fails. We have other reports that output to Excel with no problem. We think the key may be the line “The Informix server returned the following message: “Could not open or create a temporary file.”.” from the Error below.

An error occurred while performing operation ‘sqlOpenResult’ status=’-28’.

UDA-SQL-0114 The cursor supplied to the operation “sqlOpenResult” is inactive.UDA-SQL-0450 An unexpected error encountered during the “AOpen” operation.UDA-SQL-0516 The Informix server returned the following message: “Could not open or create a temporary file.”.RSV-SRV-0042 Trace back:RSReportService.cpp(758): QFException: CCL_CAUGHT: RSReportService::process()RSReportServiceMethod.cpp(252): QFException: CCL_RETHROW: RSReportServiceMethod::process(): asynchWait_RequestRSASyncExecutionThread.cpp(774): QFException: RSASyncExecutionThread::checkExceptionRSASyncExecutionThread.cpp(211): QFException: CCL_CAUGHT: RSASyncExecutionThread::run(): asynchRun_RequestRSASyncExecutionThread.cpp(824): QFException: CCL_RETHROW: RSASyncExecutionThread::processCommand(): asynchRun_RequestExecution/RSRenderExecution.cpp(593): QFException: CCL_RETHROW: RSRenderExecution::executeAssembly/RSDocAssemblyDispatch.cpp(264): QFException: CCL_RETHROW: RSDocAssemblyDispatch::dispatchAssemblyAssembly/RSLayoutAssembly.cpp(64): QFException: CCL_RETHROW: RSLayoutAssembly::assembleAssembly/RSDocAssemblyDispatch.cpp(331): QFException: CCL_RETHROW: RSDocAssemblyDispatch::dispatchChildrenAssemblyForwardAssembly/RSReportPagesAssembly.cpp(163): QFException: CCL_RETHROW: RSReportPagesAssembly::assembleAssembly/RSDocAssemblyDispatch.cpp(281): QFException: CCL_RETHROW: RSDocAssemblyDispatch::dispatchAssemblyAssembly/RSPageAssembly.cpp(287): QFException: CCL_RETHROW: RSPageAssembly::assembleAssembly/RSDocAssemblyDispatch.cpp(281): QFException: CCL_RETHROW: RSDocAssemblyDispatch::dispatchAssemblyAssembly/RSTableRowAssembly.cpp(160): QFException: CCL_RETHROW: RSTableRowAssembly::assembleAssembly/RSDocAssemblyDispatch.cpp(281): QFException: CCL_RETHROW: RSDocAssemblyDispatch::dispatchAssemblyAssembly/RSTableCellAssembly.cpp(122): QFException: CCL_RETHROW: RSTableCellAssembly::assembleAssembly/RSDocAssemblyDispatch.cpp(331): QFException: CCL_RETHROW: RSDocAssemblyDispatch::dispatchChildrenAssemblyForwardRSResultSetIterator.cpp(1652): QFException: CCL_RETHROW: RSResultSetIterator::retrieveDataQFSPartialDataset.cpp(67): QFException: CCL_RETHROW: QFSPartialDataset::GetEdgeIteratorSource/QEDmResultSet.cpp(68): QFException: CCL_THROW: QE

check the temp dir for free space and permissions
UDA-SQL-0516 The Informix server returned the following message: "Could not open or create a temporary file.