I run DNN 5.1.4, which means the current Reports 5.0.1 module, in a shared host environment.

The Reports module charting instructions mention the ZedGraph package, without specifying any particular version. So I installed the latest available ZedGraph 5.1.5 (the two required .dll) in the bin folder. Trying to get the chart, got the error message:

A critical error has occurred.
Could not load file or assembly 'ZedGraph, Version=5.1.1.428, Culture=neutral, PublicKeyToken=02a83cbd123fcd60' or one of its dependencies.
The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Found this (over 1.5 year old) thread addressing the same problem. The issue is still there.

My understanding was that I should install the ZedGraph 5.1.1 version for the Reports 5.0.1 charting to work. Yet, had a problem finding that ZedGraph version anywhere. The ZedGraph on SourceForge site (http://sourceforge.net/projects/zedgraph/files/) offers the package in many previous versions, yet version 5.1.1 is not mentioned...

After spending some considerable time and frustration, I remembered that you stressed on downloading "zedgraph .dll only" (in this very thread). In near-desperation, I went back to the ZedGraph download page (for the n-th time), and clicked on the inconspicuous looking "zedgraph .dll only", not knowing what to expect. Well, the required version 5.1.1 was there (along with some others).

The rest was easy. Found the two required ZedGraph 5.1.1 dll-s, transferred them to the bin-folder (replacing the newer version 5.1.5 that did not work), and my chart worked perfect.

Thought this experience may save someone else a bit of frustration.