Crystal Reports Parameter report saved to enterprise

Message

   I have created a report with multiple paramaters, and am trying to save it to a folder in Enterprise - but get the following error message: 

Failed to read data from report file
C:\Users\..........{...........}.rpt. Reason: Failed to read 
parameter object

I have not had this problem when saving other reports (without parameters) to the same location - what do I need to do to allow the parameter report to be saved?

Thanks
Julian