I'd like to give you here a solution I've found to the Fatal Error indicated in the title, in order to help those who would experience it too.
Our Users are geting this Fatal Error when they are clicking on the red Autodesk button in the top left corner of the Autocad Architectural 2010 menu.
After investigation, it appears those errors were starting just after the installation of the Microsoft .net Framework 4.0 on the machines in question (our company is currently deploying it on all the PCs).
Once the cause found, the solution was quit easy to find too.
All you need to do is edit the "acad.exe.config" file located in the Autocad install directory, in order to add the following line in it (between <startup> and </startup>:
<supportedRuntime version="v3.5"/>
Indeed, by default, the acad.exe.config is setup so that Autocad uses the lastest version of .net found on the machine, but the version 4.0 is not totaly compatible with Autocad 2010. By adding this line, you ask Autocad 2010 to use the version 3.5 of the .net Framework, instead of the latest version.
Problem solved.
Also, our users indicated that this change in the acad.exe.config also solved another issue they were experiencing since the upgrade to .net framework 4.0 : Their files opened from a network location were anormaly longer too open. But now everything is back to normal : No more fatal errors and not more anormaly long opening time for their files.
Hope that will help others.
