Hi Villa,
I don't know which model card you are using, but according to the specs of many of their products, they should be able to acquire data at rates much better than 20 kS/sec. Some are as high as 400 MS/sec, which is well beyond your setting.
Is the error obtained from the GageScope software or from your own vi developped from the SDK?
If it is from your own vi, can you highlight the execution and find out where the error originates from?
JLV