I ran into a similar problem.
In my case, I was unable to open Compressed Help Modules (.CHM files) with IE7.
I would get "Internet Explorer cannot display the webpage" and the URL would start with:
res://ieframe.dll/dnserror . . .
After some heavy lifting, I eventually found the following KB article. It addresses both types of problems.
You cannot open remote content by using the InfoTech protocol after you install security update 896358, security update 840315, or Windows Server 2003 Service Pack 1
http://support.microsoft.com/kb/896054
In your case, the UrlAllowList registry key should help.
In my case, the MaxAllowedZone key helped.
A key snippet:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions]
"MaxAllowedZone"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions]
"UrlAllowList"="http://www.wingtiptoys.com/;http://www.contoso.com/"
My problem opening CHM (help) files yielded error messages like this:
Cannot Open the File:
res://ieframe.dll/dnserrordiagoff_webOC.htm#mk:@MSITStore:C:\path\sample.chm
My Event Viewer (Application Error Log) had entries like these:
Event ID ( 1 ) in Source ( ITSS )
Event ID ( 1904 ) in Source ( HHCTRL )
In some cases, however, the above fix was not enough.
In those cases, the "unblock" solution described below did the job:
How to unblock downloaded Compressed Help Modules (.CHM)
http://pointerx.net/blogs/glozano/archive/2006/04/06/151.aspx
Essentially, CHM files can be unblocked by clicking "Unblock" from the "General" tab in the CHM file's "Properties" window.
For more information, see:
http://support.microsoft.com/kb/896358
The above link describes security issues involving the InfoTech protocol (A/K/A: ms-its ITS ITSS).