I am assuming you error message got truncated by accident.
Usually the member locking error means you have the the dataset in quesion open in either a viewtable form, i.e. looking at the actual data and in some cases looking at the properties of dataset such as View Columns from the SAS Explorer window.
Close down the view(s) that are open and the error will go away.
ANOVA, or Analysis Of Variance, is used to compare the averages or means of two or more populations to better understand how they differ. Watch this tutorial for more.