Report Scheduler Error

We are on Self Hosted v15 and haven't gotten the Report Scheduler to work yet.  On every report, we get the following error

Date|Component|Logger|Location|WindowsLogin|UserId|UserGroup|Level|Message
2019-05-02 10:20:48.1967|TessituraProcessingService|RunReportsScheduler|XXXXX|XXXXXXX|||Error|The system cannot find the file specified   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at System.Diagnostics.Process.Start()
   at Tessitura.ProcessingService.Services.StandardReportProcessor.StartProcess(String application, String args, Int32 requestId)
   at Tessitura.ProcessingService.Services.StandardReportProcessor.ProcessRequest(ReportRequest request, Report report, RequestOutputFormat outputFormat)

I have dug through every log &  every configuration file and I can't figure out what file it is looking for.  Any ideas?  Reports work fine when ran manually, they just don't run via the scheduler.