Issue:
You attempt to view a report in Autodesk MapGuide Viewer Release 6, but an error message similar to the following message is displayed:
Unable to display URL: file://pathname\Temp\Filename.htm

Solution:
This error occurs if you have the Autodesk MapGuide Release 6 ActiveX Control installed on Microsoft Internet Explorer 6 with Service Pack 1 installed. The functionality that the ActiveX Control is invoking has been identified as a security risk, and therefore has been turned off in Internet Explorer 6 Service Pack 1. Essentially you are no longer able to navigate from an "untrusted" zone to the "my computer" zone where the local file resides.
To add the host site to the list of "trusted" sites:


You are now able to view site.
This information was provided by Autodesk article: TS75220.