that sounds like a reasonable theory, only the one single error sounds expected and it is irrelevant.
I suggest copy the mojoportal.sln file to a new location and rename it like mojoportal.custom.sln or whatever, then copy it back to the original folder.
open the new custom solution, right click the LanguageRemover project and choose remove to remove it from the solution, it is not needed and was resulting in one build error which was just a distraction.
rebuild the solution
copy the user.config.sample file as user.config and set a connection string there for a new empty mssql db
launch the mojoportal.Web project
errors are expected at this point since the db is empty, just click continue on any error in the debugger, it should eventually redirect to /Setup which will run the sql scripts to solve the errors
if you decide to develop custom features that plugin to mojoportal, you can now add your own projects to the custom solution. any custom code should be in your own projects so this is the standard way to get started.
by coincidence I'm also coming down with scratchy throat and low grade fever, spent yesterday afternoon in bed and plan to stay there all day today as well