SQL*Loader-926, ORA-04031 unable to allocate x bytes of shared memory
If this was a one-time error, just try running SQL*Loader again.

If this happens repeatedly, you will need the help of the DBA.

The above views barely contain anything informative related to this issue. (Also there is no such view as V$SGA_TARGET or V$PGA_TARGET.) When this error occurs, the database instance creates a trace file on the database server (alert and file location can be found in the alert log), that is what you will need for further investigation.