im not sure, the person who told me to try it also used a vaio picturebook, this may just be an issues with the picturebooks compatibility, but if you install the 5.00E and you have problems like not getting level meters and error messages from your recording software, then try the 4.1A
it was a snap when i used the 4.1a. just ran the app, and installed the vx wave driver seperatly, this is something that has to be done seperatly with 2k only, read the install manual