Unity3d Project with zlib - CodePage Error

Hey folks,

I need help with implementing the SharpZibLib in a Unity3d MonoNet Project.

In the default Unity Editor everything is alright, unzipping data is no Problem.

But if I create a Webplayer-Build, the Zlib failed because of this Exception:

Init Error:System.NotSupportedException: CodePage 437 not supported
  at System.Text.Encoding.GetEncoding (Int32 codepage) [0x00000] in <filename unknown>:0 
  at ICSharpCode.SharpZipLib.Zip.ZipConstants.ConvertToString (System.Byte[ data

I tried to set another Codepage as mentioned in another thread here* , i.e.  ZipConstants.DefaultCodePage = 850; but there always occured the same Error: Codepage xx not supported. Can anyone tell, what I can do? I'm not familar with deep C# programming, I just want to use the DLL.

Thankyou!

* see other thread: http://community.sharpdevelop.net/forums/t/9524.aspx