Yet another Schema Lock post...error with shapefile only

Discussion created by Lady_Jane on Nov 3, 2011
Latest reply on Jan 6, 2012 by Lady_Jane
Hi everyone,
I have a script which creates several intermediate files saved into a temporary location.  The user is allowed to select this location.
My code loops through features 300 at a time, performs some geoprocessing operations, and attempts to add a field and populate it with the area geometry.  This always works the first time through.  Once I get to the second loop though, if the intermediate files are being saved into a folder as shapefiles (rather than a geodatabase as feature classes), I get a schema lock error when trying to add the field.  I have overwrite output set to True, and there are several other files in the same folder which are successfully overwritten before encountering this error.  The actual shapefile whose attribute table I am attempting to edit has, in fact, just been successfully overwritten before encountering this error.
I know very little about schema locks, please help :)