OPPENHEIM — Plans to erect a new town hall in Oppenheim have taken a back seat for now. The long-awaited project has run into a stumbling block: costs. Bid offers for general construction surpassed $500,000. For upstate New York counties, costs exceeding half of a million dollars are subject to a century-old state statute — the Wick's Law — which requires agencies to put out multiple bids for separate contractors. The news came as a disappointment to town officials, who hoped to have much of the work subcontracted by a general contractor. The project was formally suspended in early July, less…