We haven't received new versions of the Spanish locale files for OCS 2.1.1, so what you see in your install is what has been complete. The locale should probably be listed as "partially complete" on the website -- that's my fault, for which I apologize. If you do translate the plugins for OCS 2.1.1, we would very much appreciate an updated translation -- please let me know if you are still willing to provide, and I can give you more details.
As a side note, we are planning on releasing a new stability version of OCS in the next month or two. This new version won't have that much in the way of new locales to translate, but just the same we will be looking for volunteers to contribute to the translation process. Please let me know if you might be interested in such work; and also if you have any other questions.