Maildrop

hai,

i had created the file maildirfilterconifg with

MAILDIRFILTER=../.mailfilter
MAILDIR=.

in Maildir in virtual domain HOME directory

i got to link in my mail account and i had configured the filtering.
it has also created the .mailfilter in HOME directory.

and i had added the "| /usr/local/.../maildrop" in .qmail

after some time i get a mail which has

Subject: failure notice
Hi. This is the qmail-send program at infinite.
I'm afraid I wasn't able to deliver your message to the following
addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

:
/usr/local/bin/maildrop: Unable to create a dot-lock.
I'm not going to try again; this message has been in the queue too long