The source code is there. You need to run it from source and see where it throws. Look at the binary file and see if you have something such as COMPRESSED in the hex codes. It is impossible for me to guess at what may be causing it since I don't have the data. Open up the file in a good hex editor (UltraEdit, NPP, or 010 Editor which is what I use) and see what is happening. The code will guide you through it. Just step the code.   SAS also changed the xpt layout and I couldn't figure out the new layout (their documentation was off in one area). I don't think you have that but you need to look at the hex and see where things are off.    I looked at the code and the error you are showing doesn't tell me where the error is located (line #) or anything meaningful. There is no way you are blowing up on the value of an int and Observations is a List. Not much I can do to help w/o info and that requires stepping the code to see where it fails.   ... View more