I don't agree that a trademark on Elder Scrolls should cover just Scrolls, but it might just be a case of a legal department going through the motions.
See Trademark Coexistance http://www.wipo.int/wipo_magazine/en/2006/06/article_0007.ht...
SparkFun vs SPARC International http://www.sparkfun.com/news/344
Bathesda's lawyers probably felt that the two titles are similar enough in either gameplay style or genre that it could be infringement. Unfortunately, there isn't any other way of resolving this than suing the people you believe are infringing on your trademark.
I really don't understand how they can reasonably expect to own the trademark on a word that is only a portion of their actual product line and describes an object that has been known to exist for thousands of years. Microsoft was denied the trademark for "Windows", but they were given trademarks for the phrases "Windows XP Operating System", etc.
Also, MS does have a registered trademark for "Windows"(http://www.microsoft.com/about/legal/en/us/IntellectualPrope...), but this is only for computer operating systems, not for physical building windows.