Some recovery procedures ask you to submit an SPR (Software Performance Report). This means to signal the error to either the CLASS authors, the local contact person, or the system manager. Signalling the error does not mean simply just telling ``Gee, I typed ABRACADABRA and the program crashed'', it implies at least giving a copy of the CLASS.LOG and CLASS.MES files, and if requested, of the data files used when the error occured. The utilities are too complex to allow any action if these files are not given.
Please remember that if you do not signal errors, they will (at best) never be corrected. At worst, hardware errors which would have been recoverable when signalled in time may become completely unrecoverable.