Bad Mails

Hello to all.
I am processing mail using CDONTs.
All works fine until yesterday all of a sudden on my IIS SMTP server in
badmail directory I start getting messages with following contents:
Unable to deliver this message because the follow errorwas encountered:
“Error is processing file in pickup directory.”.
The specific error code was 0xC00402CE.
Of course original messages ends up in badmail as well.
Can anyone help me fix this?
Thanks.