1. A data processing system suitable for use as a component in a computing grid, comprising: means for generating a request for proposal (RFP), the RFP being descriptive of a data processing task; means for providing the RFP to a plurality of resource providers via the computing grid, wherein each of the resource providers is potentially suitable for performing the data processing task on behalf of the resource consumer; and an RFP response processor configured to receive and evaluate an RFP response generated by one of the resource providers responsive to the RFP; and an exception processor accessible to the RFP response processor and configured to evaluate an exception in the RFP to determine if the exception disqualifies the RFP response.