Error when running Batch Task "Update Main Translation Memory"

When trying to run the Batch Task "Update Main Translation Memory" I get the following error:

Unexpected exception when configuring file multiFileConverter for task 'Master-Translation Memorys aktualisieren': Failed to create an instance of translation provider 'sdltm.file:///...

Interengstingly it worked before. I am working with the API of SDL Trados Studio 2014 SP2

From the same machine I can access the file manually so there's no problem with access rights.

Since I do not get back any stack trace, I cannot find out what actually occured. The line of code (VB) that throws the error is:

Dim UpdateTMTask As AutomaticTask = sdlProj.RunAutomaticTask(sdlProj.GetTargetLanguageFiles.GetIds, AutomaticTaskTemplateIds.UpdateMainTranslationMemories)

 

.NET-Version is 4.5

 

Any thoughts on this?

 

Best regards

Thomas