Being the good boy that I am, I attempted an  upgrade of one of my test sites from 5.1.0 to 5.1.1 and I get the error below. 

I realized the work around is to go grab the system.web.extensions.dll from the 5.0.0 (or 5.0.1) bin directory.  But this issue was identified with the upgrade in last release and still seems to be there.

There has to be a better way of doing upgrades than replacing and hand editing the web.config file each time.  The hand editing is error prone and it leads to issues like this one.

I realize there are alot of folks working very hard to make dnn work and I do appreciate it, so please take my comments in a constructive light.

Thanks...

Configuration Error

Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: Could not load file or assembly 'System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Source Error:

Line 126:        <add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
Line 127:        <add assembly="System.Management, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
Line 128:        <add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
Line 129:      </assemblies>
Line 130:      <!-- register your app_code subfolders to generate granular assemblies during compilation

WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Hi Alex,

Thanks for the pointer on the merge, I never knew that.  I simply followed the directions that are in the ~/Documentation/Readme.txt file.  I guess there should be an issue opened in gemini for that?  As I just upgraded another one of my test boxes by simply dropping the upgrade into the directory, very cool.  You saved me hours of work and trepidation.

As for the upgrade issue being in gemini, I don't know.  But the issue was discussed here and the resolution was to fetch the dll from the older package and let the upgrader reupgrade.  http://www.dotnetnuke.com/Community/Forums/tabid/795/forumid/107/threadid/315838/scope/posts/Default.aspx

Thanks again!

Jeff

Someone may correct me, but I think this is the wrong advice.
You need that dll installed in the servers GAC for DNN 5. This is different to DNN 4.
If you are running .NET 2.x you should have AJAX extensions installed on your server.
If you have .NET framework 3.5 SP1 running then AJAX comes bundled and I don't think you need this.
As future version of DNN 5 will require .NET framework 3.5 SP1 the obvious thing to do is get this up and running on your server. You then need to make sure you point to the correct web extension dll for 3.5 and delete that dll you copied across.