。
She's hard up for money.
Literal
She [topic-は] money [in-に] is-troubled.
困る ('to be troubled, be in difficulty') takes its source of trouble with に — with money: 金に困る ('troubled by money / strapped for cash'). The same に appears with other verbs of distress: 苦しむ ('suffer'), 悩む ('agonize'). Note that 金 here without honorific お~ tilts the register toward bluntness — a grim, no-frills statement of penury. The resulting state ~ている frames the trouble as ongoing rather than momentary.