。
She does nothing but pick at other people's flaws.
Literal
She [topic-は] others [genitive-の] flaws [only-ばかり] is-searching-for.
あら ('flaw, fault, defect — especially of a person') is a colorful native Japanese noun, often associated with the compound あら探し ('fault-finding'). The pattern [object]+ばかり+[verb-ている] ('do nothing but X / always X-ing') marks a habitually one-track behavior. ばかり here is the focusing 'only / nothing but,' carrying a slight critical undertone — the implication is that the speaker disapproves of this behavior. The combination suggests a chronic fault-finder or critic.