In the function definition
m2p(c1,c2,t1,t2, b0,b1,b2,tau) := (c1*((1 + 0.01*ns(b0,b1,b2,tau,
t1))^-t1))
+
(c2*((1 + 0.01*ns(b0,b1,b2,tau,
t2))^-t2));
try changing the names of the first two arguments to something like
k1 and k2; thus
m2p(k1,k2,t1,t2, b0,b1,b2,tau) := (k1*((....
I think this will fix your problem. In Maxima, identifiers of the
form ci,di, and ei, i=1,2,... get bound to command lines or display
lines.
c1 & c2 are fairly natural choices for identifers; however, they cause
trouble in Maxima. We've talked about changing the identifiers for command
and display lines.
Barton