Can't upload vsix package to marketplace

Hi,

I don't seem to be able to upload a package to the visual studio marketplace. I keep getting the same error: "Extension package contains invalid characters.". What am I doing wrong?

<PackageManifest Version="2.0.0" xmlns="http://schemas.microsoft.com/developer/vsx-schema/2011"><Metadata><Identity Id="SampSharpVisualStudio" Version="0.1.0" Language="en-US" Publisher="ikkentim" /><DisplayName>SampSharpVisualStudioPlugin</DisplayName><Description xml:space="preserve">A plugin that allows you to build and debug SampSharp projects.</Description><MoreInfo>https://github.com/ikkentim/sampsharp-visualstudio</MoreInfo><License>LICENSE</License><Icon>SampSharp.VisualStudio.ico</Icon><Tags>sampsharp, mono, debugger, project, template</Tags></Metadata><Installation><InstallationTarget Id="Microsoft.VisualStudio.Community" Version="[14.0]" /></Installation><Dependencies><Dependency Id="Microsoft.Framework.NDP" DisplayName="Microsoft .NET Framework" Version="[4.5,)" /><Dependency Id="Microsoft.VisualStudio.MPF.14.0" DisplayName="Visual Studio MPF 14.0" Version="[14.0]" /></Dependencies><Assets><Asset Type="Microsoft.VisualStudio.VsPackage" Path="SampSharp.VisualStudio.pkgdef" /><Asset Type="Microsoft.VisualStudio.ProjectTemplate" Path="ProjectTemplates" /></Assets></PackageManifest>

Thanks in advance,

Tim