DNN : 4.5.1
Reports Module: 4.4.2

InnerException: Nome di percorso vuoto non valido.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.IO.StreamReader..ctor
StackTrace:
Message: DotNetNuke.Services.Exceptions.ModuleLoadException: Nome di percorso vuoto non valido. ---> System.ArgumentException: Nome di percorso vuoto non valido. in System.IO.StreamReader..ctor(String path, Encoding encoding, Boolean detectEncodingFromByteOrderMarks, Int32 bufferSize) in System.IO.StreamReader..ctor(String path) in DotNetNuke.Modules.Reports.Visualizers.Html.Visualizer.DataBind() in DotNetNuke.Modules.Reports.Visualizers.Html.Visualizer.Page_Load(Object sender, EventArgs e) --- Fine dell'analisi dello stack dell'eccezione interna ---

That error is strange, because it seems to be coming from code in the HTML Template Visualizer...are you sure you are running the Grid Visualizer? Did you at some point switch to the HTML Visualizer and then switch to the Grid Visualizer?

Andrew Nurse
DotNetNuke Core Team Member and Reports Module Project Lead
Microsoft Certified Professional Developer