You should use SSV2 method for ASUS Eee PC's. Sometimes you need to try more than once. It may fail on the first try, if so try clicking GO again and see what happens.
In as much as you got the error message, in the sense saying that there is not enough room for the slic, i can surmise that you either have the 1201ha or 1201hag model. Either way, andyp's tool always defaults to ssv3 method (for eeepc bioses), when it opens and the original bios file is selected. I think you failed to click on the [advanced] button and then select [adjust location of slic] under the ssv3 options. Just do it now, and you will be okay.