。
She's taken on too much work.
Literal
She [topic-は] many [genitive-の] work [object-を] take-on-too-much is.
引き受け過ぎる is a triple-stack: 引き受ける ('take on, accept responsibility for') + 過ぎる ('exceed') in compound-verb formation, then ~ている for the resulting state — 'is in the state of having taken on too much.' The ~過ぎる ('do too much / be too X') auxiliary attaches to verb stems and to adjective stems (食べ過ぎる 'overeat,' 大き過ぎる 'too big') and is very productive.