Btw, posting the same question once is usually enough heh.
I have the e505 myself. What headphones are you using with your flash player? I haven't had to go past volume-15 with any of my headphones yet. It's possible you're using a set of inefficient cans, but we'll find out.
Seriously, I can't go anywhere near the volume cap or my ears hurt. Either you are going deaf, your player is broken or you are using high impedance heaphones. Hopefully it isn't one of the first two reaons.