Hi Sebastion, I did the following,
I edited the "LanguageEditor.ascx.vb" per Jose's fix, and confirmed it resolved my problem.
I remove the fix and confirmed the problem was back
I copied the entire Compilers section from the release.config which came with DNN 5.5.0 into my web.config, replacing what I had (I could see no difference, but figured copy/paste was easy test).
The compiler settings did
not resolve the problem.
Here is what I copied from release.config, not sure if it will post correctly:
<compilers>
<compiler language="vb;vbs;visualbasic;vbscript" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" extension=".vb" warningLevel="4">
<providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="OptionInfer" value="true"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
<compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider,System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="4">
<providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
</compilers>