Chicago-based Corus Bankshares said $345 million worth of South Florida condominium loans in its portfolio are more than 90 days past due, up from $252.6 million in the first quarter of the year. Corus has a $1.5 billion commercial loan portfolio and is involved in 19 South Florida projects. Corus also reported two potential problem loans totaling $281 million in balances and commitments in South Florida, down from the first quarter, when it had three potential problem loans here totaling $301 million. Stalled construction, cost overruns and slow sales are the projects’ main obstacles. The company took a net loss of $16.2 million, or 30 cents a share, in the second quarter.