Error: encoding iso-8859-1 not supported

[b_picardi]

I use Tweetinvi API v.3.5.2 in a .NET Web application and everythink works fine. I send twits programmatically with text and an image.
Now in a new Silverlight app I’m trying to do the same but I’m getting this strange behaviour:

• My app gets this error message on this instruction “Tweet.PublishTweet(Twt)” that says:: encoding name ‘iso-8859-’ not supported. parameter name.
• If a send the exactly same message with the same image manually on the web I have no problems.

Because the code I use is exactly the same that works fine in my .Net Web app, and because I send the message manually without any problem, I don’t know how to solve the problem.

Any suggestions? What does it mean the error message? Attached is a image I try to send inside the message

[ePirat]

Sounds like you are running into some encoding problems unrelated to the Twitter API. I guess there is a bug in your code somewhere.

[b_picardi]

This problem is related to Silverlight applications only, The encoding bug should be in Teetinvi library when running in Silverlight environment.
My code is exactly the same that works fine in my ASP:NET application.
TweetinviAPI version: 0.9.8.2 installed by Nuget on Visual Studio 2013.