Yamaha DTXpress/DTXplorer/DTXtreme

I'm not sure if anyone else has had the same problem, but I have a 
DTXPRESS I.  I haven't played it that much at all due to school 
(sadly), but when I do play I've found that I can't get the screws 
tight enough to prevent the pads from dropping when I play.  And I 
don't even play hard.  However, I've found that trying to get these 
tight enough to hold the pads up has stripped all of the screws out!  
Does anyone know of any way to fix it or if it's possible to order a 
bunch of these screws from Yamaha?  I currently just have bolts going 
through the clamps with a wing nut on the other end, but it requires a 
screwdriver and pliers to get it tight enough.  I'm hoping there's some 
way to do fix it that would allow me to get them tight enough by hand.  
Any advice or help would be greatly appreciated!!