Error: The language resource file could not be located.

I am trying to build a standalone app based on the sample project "Sdl.SDK.LanguagePlatform.Samples.TmLookup". When I try to do a concordance search in an existing TM, the following code is generating an exception:

results = Connector.fileTm.LanguageDirection.SearchText(GetSearchSettings(target), searchText);

The exception is:

LanguageResourceFileNotFound    160    The language resource file could not be located.

I am able to access the TM and read the number of translations units as follows:

Connector.fileTm.GetTranslationUnitCount().ToString()

Any ideas what the problem could be? I thought it might be a permissions problem, so I moved the TM into the same directory as the C# app, but I get the same error.

EDIT: I just realized I might be misunderstanding what a "language resource" is. I thought it was the TM itself, but it is actually "a set of settings in a translation memory" (http://producthelp.sdl.com/glossary/en/glossary.shtml#language%20resource).

Thanks,

Gary