This paper describes a project developed within an ongoing study at the University of Athens. In our previous studies we analyzed the errors of Greek learners of Italian language, using Learner Corpora evidence and we retrieved useful information about their interlanguage and its interaction to the language learning process. In this study we assume interlanguage is a tool that can help us to distinguish the language errors from the translation errors and identify the most frequent errors and the causes. For this reason, we focus on specific linguistic areas and we examine a learner translator Corpus. The results are interestingly different from the ones that a language teacher would expect.