The ghost of gain-on-sale accounting continues to haunt subprime lenders who are seeing their earnings dragged down by lingering problems with residual valuation. A case in point is Aames Financial. In its recently released earnings report for the fiscal year ended June 30, the California-based lender reported a solid $3.1 million in earnings from operations. But those earnings were undercut by a $33.6 million writedown of the carrying value of its interest residuals. That left