Hello Wayne,
Thank you for your words. You are probably right. But the problem is not with Windows Server 2008 itself.
I installed a VM with Windows Server 2008, SQL Server 2008, and all the same stuff that I have on the production server.
The only difference is that the production is Server 2008 Standard and this VM is Server 2008 Enterprise.
I upgraded from 4.8 to 4.9 on the VM and had no problem! First try, first prize!
But I found something different.
When I log in as host and access the Host Settings under Host menu, the DNN shows us under the configuration the permissions we have available.
On Production Server i have this: ReflectionPermission, WebPermission
On the Test Server I have this: ReflectionPermission, WebPermission, AspNetHostingPermission
Somehow on my production server I havn't configured the AspNetHostingPermission.
Since I have plesk installed, the server configuration was automatic and now I'm a little lost...
My guess is that 4.8 version doesn't nedd the AspNetHostingPermission, but 4.9 version does!
Can someone confirm this to me?
Does anyone as a ideia on how to give the AspNetHostingPermission to the site or the IIS server?