Hi I am also using DNN and getting the sam error for the dxo.
the last comment from Nick made me think about the DNN structure "ASPxGridView scripts are not loaded"
I think I have the solution for this problem.
When you set up the DNN you always try to get the best performance possible. So if you can log on as a "Host" the first thing you do is going to "Host Settings"->"Performance Settings" and you probably put the maximum caching for everyting and compression and check use whitespace filter .
And that is the problem ( took me a while to find this out)
If you check the "Use Whitepace Filter" you will get this error, but if you uncheck it, everything will work fine
Please try this, hope it helps.
-RAZ-