Yeah, there is a size limit to the bitmaps you use in the WPS. I've hit this wall several times trying to make really cool WPSs.
I haven't looked hard at your code yet, but if you currently redraw the ENTIRE volume bar, you may want to instead only draw what changes between each volume level, so you only have 11 small boxes that follow the arc of the volume display. Then you'll also not have any problems with the volume display drawing over the "shuffle" in the corner.
You can't do this with the progress bar, so that you may have to scrap for something more linear.
I really like the look of this WPS so far, so I hope you can solve these problems.