Same issue here. I'm using SMS 12.2.7. Nothing too special about the model except that the flow in the model is mostly supercritical. I had several model run attempts fail presumably because I hadn't yet modified the terrain to provide openings at culvert crossings. When I finally decided to modify the terrain and rerun the model, I got the same error message as above:
*Program stopped due to the following:
*Time_Series data file does not exist!
*Error Code is: 6
I even got rid of the unsteady boundary conditions and tried to run the model in steady mode (thereby eliminating the need for a time series), but I still get the same error. SRH-2D model files are attached, if that helps.