DodgyEdgy is right. When you "resample" something in Soundforge, it applies it to the whole file. So, pasting the two together and then resampling will not work. In the lower corner of your soundforge screen, the sampling rate of the file you have in view should be shown. Pick whichever file has the highest sampling rate, and then "resample" the other file at that rate. Or, to make your life even easier, just resample both files to "44,100" when they are open. Then, highlight the one you wish to paste in, copy it, and paste it in. You will no longer have the same problem.