Debug it.
Check what value you are getting for
Server.MapPath("RptCustomerDeposits.rpt")
and then check that teh file is actually there. I suspect it works o0n your local machine because the file exists, but it may be that you are expecting a client file on the server, which is not going to work. The first thing you need to know is: "where is it looking?" and "Is the file actually there? If not, where is it?"