Firstly, thanks for IIRF, it's a very useful bit of software.
I just implemented it on our production server and I am seeing a bunch of these same errors:
Event Type: Warning
Event Source: Ionic Isapi Rewriting Filter
Event Category: None
Event ID: 1
Time: 2:39:29 AM
The description for Event ID ( 1 ) in Source ( Ionic Isapi Rewriting
Filter ) cannot be found. The local computer may not have the
necessary registry information or message DLL files to display
messages from a remote computer. You may be able to use the
/AUXSOURCE= flag to retrieve this description; see Help and Support
for details. The following information is part of the event: IIRF: event
ID 1, Invalid Parameter: expression((null)) func((null)) file((null))
I looked in the IIRF log file but there is nothing relevant there (the only warning is about a line in the config file that starts with a #:
ReadSiteConfig: WARNING: line 1: unrecognized directive, ignoring it: '#'
This is running on Windows 2003 Server (SP2) with IIS6. Interestingly, our dev machine (which runs the same software) isn't showing any of these errors. I am wondering if it is a response to some sort of malformed request that is coming across the internet?
Let me know if there is any more information I can provide to help get to the bottom of this,