arcpy - Cannot get rid of lock on file geodatabase and feature class created in Python script

I have a python script, (for ArcGIS 10), that creates a new file geodatabase, creates a new feature class in that file geodatabase and then reads data from an SDE feature class to populate the new feature class. The script runs fine, except that a lock is placed on the file geodatabase that persists after the script is complete. The database cannot be deleted with ArcCatalog. Once the new feature class is deleted, then the file geodatabase can be deleted.

In the script I delete the references to all cursors and rows and yet still the lock remains. Below is the relevant code. What am I doing wrong?

import arcpy

OutputFolder = arcpy.GetParameterAsText(0)
FGDName = arcpy.GetParameterAsText(1)

StringInputWorkspace = arcpy.GetParameterAsText(2)

SourceFCAddressPoints = StringInputWorkspace + '\\sde.ERLANDSEN.AddressPoints'

## Create File GDB...
Output_gdb = OutputFolder + '\\' + FGDName + '.gdb'
arcpy.CreateFileGDB_management(OutputFolder, FGDName)

## Set current workspace to to file geodatabase
arcpy.env.workspace = Output_gdb

NewAddressPoints = Output_gdb + '\\AddressPoints'

## Create Feature Class...
arcpy.CreateFeatureclass_management(Output_gdb, "AddressPoints", "POINT", "", "DISABLED", "DISABLED", "PROJCS['NAD_1983_StatePlane_Washington_North_FIPS_4601_Feet',GEOGCS['GCS_North_American_1983',DATUM['D_North_American_1983',SPHEROID['GRS_1980',6378137.0,298.257222101]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]],PROJECTION['Lambert_Conformal_Conic'],PARAMETER['False_Easting',1640416.666666667],PARAMETER['False_Northing',0.0],PARAMETER['Central_Meridian',-120.8333333333333],PARAMETER['Standard_Parallel_1',47.5],PARAMETER['Standard_Parallel_2',48.73333333333333],PARAMETER['Latitude_Of_Origin',47.0],UNIT['Foot_US',0.3048006096012192]];IsHighPrecision", "", "0", "0", "0")

## Add fields
arcpy.AddField_management(NewAddressPoints, "AddressPointID", "LONG", "", "", "", "", "NULLABLE", "NON_REQUIRED", "")

curSourceAddresses = arcpy.SearchCursor(SourceFCAddressPoints)
curNewAddressPoints = arcpy.InsertCursor(NewAddressPoints)


for rowSourceAddress in curSourceAddresses:
    rowNewAddress = curNewAddressPoints.newRow()
    rowNewAddress.SHAPE = rowSourceAddress.SHAPE
    rowNewAddress.AddressPointID = rowSourceAddress.OBJECTID

del rowNewAddress
del rowSourceAddress
del curSourceAddresses
del curNewAddressPoints