。
She seemed startled at being called by name from behind.
Literal
She [topic-は] [from-behind-背後から] own's name [object-を] was-called and [startled-びっくり] is-doing [seems-ようであった].
A passive-of-suffering construction: 自分の名前を呼ばれて — 'had her name called.' Japanese passives often describe situations where the subject is affected by an action (frequently with a slight sense of inconvenience or surprise). びっくり is a state mimetic for being startled. ~ようであった is the past-tense evidential 'seemed.'