Windows Defender makes mysterious folders and files

Hi,

A)
I have Win XP Pro SP2.  I installed Windows Defender.  I have run Windows Defender.  I don't "use real time protection" because I have another antispyware program running.

Now weird folders and files are being created in the root folder containing "My Documents".
Below are the folders and files.
1. FOLDER      F:\9de1bcc46e6629e5b6d4f3fdd96e\
FILE      AS_Delta.ini
FILE      mpasdlta.vdm
FILE      MPSigStub.exe

2. FOLDER      F:\Config.Msi\

3. FOLDER      F:\fe851fd572d87c6e7b7f16432944fc\
FILE      AS_Delta.ini
FILE      mpasdlta.vdm
FILE      MPSigStub.exe

B)
Why do I assume Windows Defender is the culprit?

Because here are the contents of "AS_Delta.ini" (one of the files in one of the folders in question).

****Start AS_Delta.ini contents****
"; MpSigStub INI Configuration File

;----------------------------------------------------
; Configuration Section
;
; This section specifies parameters for the stub
;----------------------------------------------------
[Parameters]
PATCH_FULL_ENGINE=0

;----------------------------------------------------
; Products Section
;
; These sections specify the products that are to
; be updated.
;----------------------------------------------------
[WD]
PRODUCT_NAME=Windows Defender
PRODUCT_CONFIG_ROOT_KEY=SOFTWARE\Microsoft\Windows Defender

[MCP]
PRODUCT_NAME=Microsoft Client Protection
PRODUCT_CONFIG_ROOT_KEY=SOFTWARE\Microsoft\Client Protection"
****End AS_Delta.ini contents****

Questions:
1. Is "Windows Defender" the culprit?
Supporting evidence are "PRODUCT_NAME=Windows Defender
PRODUCT_CONFIG_ROOT_KEY=SOFTWARE\Microsoft\Windows Defender"

2. Why is this happening?

Thank you.