Hello Wiewiek,
The required Nevron assemblies are in the GAC, however they can't be found properly. You will also have to copy the assemblies to the virtual directory of the SharePoint application (in the Bin folder).

For example: from the Nevron SharePoint Vision installation folder:
- for SharePoint 2007 “C:\Program Files\Nevron Software\Nevron SharePoint Vision 2010.1 for MOSS and WSS 2007\Bin”
- for SharePoint 2010 “C:\Program Files(x86)\Nevron Software\Nevron SharePoint Vision 2010.1 for MOSS and WSS 2010\Bin”

Copy: Nevron.Presentation.dll; Nevron.Chart.dll; Nevron.Chart.Template.dll; Nevron.System.dll

Paste the assemblies in: “C:\Inetpub\wwwroot\wss\VirtualDirectories\YourWebApplication\bin”

Hopefully this helps.

I added a code to calculate cummulative sum of the second value in the chart via code injection.  When I hit the "Compile" button, it gave me the following error:

Info:

Compiling...

error CS0006: Metadata file 'C:\WINDOWS\assembly\GAC_MSIL\Nevron.System\10.5.31.12__6a987feae5e496fd\Nevron.Presentation.dll' could not be found

error CS0006: Metadata file 'C:\WINDOWS\assembly\GAC_MSIL\Nevron.System\10.5.31.12__6a987feae5e496fd\Nevron.Chart.dll' could not be found

error CS0006: Metadata file 'C:\WINDOWS\assembly\GAC_MSIL\Nevron.System\10.5.31.12__6a987feae5e496fd\Nevron.Chart.Template.dll' could not be found

Compiled with 3 error(s).

I had checked that the Nevron.*.dll are in GAC and this is what listed for "Referenced Assemblies" (I left it as default).

What do I need to do to get the code injection to work? Should I copy the dll files to the