"herself" is a reflexive pronoun. Both "herself" and "her" can be used as an object for verb or preposition. However, one thing is different between them. Since "herself" is reflexive, so whatever the verb does will reflect back, for example:
She bought herself a new car.
Here, you use "herself", because you want to mean "she bought a new car for herself", not anybody else.
If you use
She bought her a new car.
Then "her", might be her mother, her daughter, ... might NOT be herself, because "her" is not reflexive.
Now, let go back to your questioned sentence.
In the sentence, the subject is "Mrs Count's background", NOT " She". If you use "herself", it doesn't reflect back to her. Hence, you CANNOT use "herself".
2013-02-26 13:31:38 補充：
let go ... ==> let's go ...
2013-02-27 09:13:29 補充：
I was wondering where Panda went. Now, I know, you are busy with getting your daily fill with bamboo shoots.
2013-02-27 23:21:02 補充：
小弟弟 ! You have asked a very nice question. Such a question allows you to understand, studying and memorizing grammar rules will not help you in answering this kind of question.
2013-02-27 23:23:44 補充：
Instead, using a logical thinking while studying English will help you better. Something you need to know grammar is dead, however, human being's thought is alive. It is hard to use a dead rule to master a live thought.
2013-02-27 23:25:00 補充：
Besides, we use language to communicate with each other based upon logics. Hence, it is better you place a little thought while studying English.