Well, I havent used 4.3.5 yet but I do recall in 4.3.4 that after changing the names in the App_Code and DesktopModules folder, whenever you are using C# module you must tell the compiler and you specified it in the web.config file under <codeSubDirectories> :
<!--register your app_code subfolders to generate granular assemblies during compilation -->
<codeSubDirectories>
<add directoryName="Change this to the name of your C# module"/>
</codeSubDirectories>
If version 4.3.5 didnt provide this web.config update using the starter kit then this may be your problem.
MW