blank page in IIS log

I've been having problem with the w3c extended log in IIS 4.0. The web log is creating blank page at the beginning of the log file. This happens randomly... (works fine 1 day & next day it breaks it again).

1. I have no idea what's causing the problem.
2. Why the log was created every day at 04:00 p.m. instead of 00:01 a.m.?
3. How do you change the creation time of the log?
4. Is that why the log is corrupted if the log creation happens during the pick time of the web site

below is the w3c log without the header

<blank page><blank page
2004-03-02 04:08:39 11.25.48.56 - W3SVC2 MWINTRA 11.16.4.76 GET /mw_eforms/ViewEForms.asp 401 5 744 80 HTTP/1.0 Mozilla/4.0+(compatible;+MSIE+5.5;+Windows+NT+4.0

Without an healthy log, I won't be able to generate the web report using site server 3.0. I will get this error on Site Server

"Error querying the import job. Site Server could not detect the log file format of the following log data source: Log data source

Please help. Thanks!

migreen
Thu Jul 15 00:23:48 CDT 2004

Are you saying the header information is missing and/or there is a lot of
white space before the log starts again?
Do you have any 3rd party applications that write log information?
Do you have to do anything to the server for the log to start working again
from one time to the next?
Is there a pattern to when it stops working (same day/time)?
Are you logging to the default directory?

Thank you for choosing Microsoft
Miriam Lamaute
Microsoft Developer Support

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