Cannot Save Case

We are unable to save the case and we get an error when we try to save a case either from the 'file...save case' or 'file......save case as' or the main button of the left-hand settings that shows 'save case'. All three result in the following error:
'Create STDoseCseName dll could not be loaded. Error number=-2147221164 Class not registered. Change save settings to use standard save.
I've tried trouble shooting this myself and with our IT dept. We have an virtual FEMA exercise in less than 3 weeks where we need to be able to save the cases we run to provide to FEMA as documentation of the exercise response.