I think you have a modified HF script .The code you post in line 3431 does not have this command.
The full command is in line 3425 where the full code is
IF EXIST SOURCE\I386\SP%SP%.CAB (
DEL/Q/F SOURCESS\I386\SP*.CAB&MD WORK\SPUP&EXPAND SOURCE\I386\SP%SP%.CAB -F:* WORK\SPUP
XCOPY/DEHY WORK\SPUP SOURCESS\I386\DRIVER
ECHO Merged extracted driver packages into one folder
ECHO>WORK\TXTSDATA.TXT DriverCabName=DRIVER.CAB
FINDSTR/VBI "DriverC SP1.CAB SP2.CAB SP3.CAB SP4.CAB SP5.CAB" SOURCESS\I386\TXTSETUP.SIF>TXTSETUP.SIF
MOVE/Y TXTSETUP.SIF SOURCESS\I386
IF EXIST SOURCESS\I386\DOSNET.INF (
FINDSTR/VI "\,SP1.CAB \,SP2.CAB \,SP3.CAB SP4.CAB SP5.CAB" SOURCESS\I386\DOSNET.INF>DOSNET.INF
MOVE/Y DOSNET.INF SOURCESS\I386
)
)
Looking at it, it will only delete if ----> IF EXIST SOURCE\I386\SP%SP%.CAB <-----
I'm using hfslip-1.7.10_beta_J.cmd