I am using a DAQCard 6533, which uses the Traditional DAQ drivers. From time to time I get error 10409 (because I have input some incorrect parameters, or something). The only way I have found to clear this error so that my VI functions properly again is to shut LabVIEW down, completely, then restart it. This is extremely frustrating, as my laptop is slow and it takes about 3 minutes to shut it down and restart it.
This error is likely coming up because you are at some point in your code trying to access a port that has been previously configured for another task. This will bring about the error 10409. Here is a Knowledgebase article that mentions this error and the way around it. Basically the easiest way to take care of that error is to add a Device Reset.vi before you have your DIO Config.vi.