So you've got a nightly process that updates a file somewhere. Unfortunetly, something still has it locked and the update fails, the nightly process crashes & burns, and someone at 8am upon arriving decides to blast you for not having updated data ready for them to analyze. Sound familar?
There are a variety of strategies to address these issues, but they are vast, sometimes complex, and vary depending on the environment, software, etc available or in use at your site.

Included is a brief list of references available on this specific issue. If you have other recommendations, please share them!

1. SAS User Group Poster: http://www.lexjansen.com/pharmasug/2005/posters/po33.pdf provides a useful way to check for whether the table is available, or fail more gracefully
2. pg 8 of NESUG presentation: http://www.nesug.org/Proceedings/nesug09/ff/ff01.pdf suggests setting the option for "Close data grid after period of inactivity (specify in minutes) " to 20min. 
3. Stopping an object spawner and all .sas spawned jobs before running the ETL process will ensure that all locks are off in an Integrated Technologies environment (such as EG, BI, etc)
4. Restarting the OLAP Server prior to OLAP Cube batch updates usually ensures that all locks are off.