@Twigs— this is an old problem that started in RM 8-- clicking thru a list kind of fast is when it shows up-- by using either / or index list or chevrons next to name and it shows up somewhere between 650 and 1000 click generally ( or in your case every 30 minutes).
Once the error happens you need to close RM and run the tools as Jerry said-- I have at times rebooted the computer–seems to slow down the argument out of range errors.
Typically this is the only time I get argument out of range errors BUT???a