Question: Procedure with empty plot

restart:with(plots):

Nb:=0.5:Nt:=0.5:G:= 2:B:= 2:beta:= .2:Q:=2: alpha:= 2:

de := diff(alpha*f(y), y, y, y, y)+G*(diff(theta(y), y, y))+B*(diff(phi(y), y, y))

+6*beta*(diff(f(y), y, y))*(diff(f(y), y, y, y))^2+3*beta*(diff(f(y), y, y, y, y))*

(diff(f(y), y, y))^2 = 0, diff(theta(y), y, y)+Nb*(diff(theta(y), y))*(diff(phi(y), y))

+Nt*(diff(theta(y), y))^2 = 0, diff(phi(y), y, y)+Nb*(diff(theta(y), y, y))/Nt = 0:

p:=proc(x) local res,R1,R2,F3,param; global de;
option remember;
if not type(x,numeric) then return 'procname(x)' end if;
R1:=evalf(1+.1*cos(x));
R2:=evalf(-1-.5*cos(x+.4));
res:=dsolve({de,f(R1) = 0, f(R2) =0, D(f)(R1) = -1, D(f)(R2) = -1,theta(R1)=0,

theta(R2)=-1,phi(R1)=0,phi(R2)=1},numeric,output=listprocedure,maxmesh=1024);
param:={G = 2, B = 2, beta = .2, alpha = 2}:
F3:=subs(res,eval((alpha+3*beta*(diff(f(y), y, y))^2)*(diff(f(y), y, y, y))+

G*theta(y)+B*phi(y),param));
F3
end proc:

plot(p(x),x=0..1);

Warning, unable to evaluate the function to numeric values in the region; see the 

plotting command's help page to ensure the calling sequence is correct