I have a 8 mb wav file. When i try to load it i got “System.ArgumentOutOfRangeException”.
Other wav files working normally.
Ever wonder if you answered your own question? 
Joking aside, are the others larger than 8MB?, I would assume 8MB+ was fine as most WAVE files with audio lengths longer than 10-30-120 seconds will easily hit higher than this, so my assumption is that there is an issue with the creation of that file, was it created on your system that is giving the error? perhaps re-encode the file?
Have you stepped through the code a bit, first at least seeing which argument is out of range?