Are you using AJAX? Maybe an in-place text editor? Or one of those fancy “click the star to rate this” jobbers? Or see result of arithmetic calculation. It was that latter case for me.

@tatal_payable = (@total_event_payable.to_f – @coupon.value.to_f)
render_text @tatal_payable and return

where the @tatal_payable was a Float. Rails gave this strange error message: (more…)