We had the same problem, but what resolved it by saving the file on another drive then moving it to the appropriate drive. For example, it didn't work transferring to our F: drive, which is our server, but it did work saving to the local computer, C: drive, then moving over to the F: drive after the fact. 

Once transferred to the Info Return System from EasyAcct via C: drive, you move it over to whichever network you are using; in our case, it was the F: drive.