Verilog Question with Quartus.

Are you setting parameter values through Quartus or in your source code? I'm guessing Quartus since I can't imagine a source file change not being seen. When you set parameters through Quartus they will end up in your .qsf file. If that's what's going on then after you change the value, check your .qsf file and see if the change is reflected. Maybe you need to push the "Apply" button after making the change? And after changing the value you'll have to re-synthesize for it to take effect.