Error using lbfgs



Hello.

I'll try to use lbfgs and got this:
===================[cut]============================================
(%i2) V: 0.75$
a: 24$
b: 68$
C(r) := 2*%pi*b*r^2 + 4*a*%pi*r + 2*b*V/r + a*V/(%pi*r^2)$
lbfgs(C(r), [r], [1.0], 1e-4, [1,0]);
(%i3) 
(%i4) 
(%i5) 
(%i6) *************************************************
  N=    1   NUMBER OF CORRECTIONS=25
       INITIAL VALUES
 F=  8.365790735841403D+02   GNORM=  1.042646940618427D+03
*************************************************

   I  NFN     FUNC                    GNORM                   STEPLENGTH

Maxima encountered a Lisp error:

 Error in NTH [or a callee]: T is not of type SYSTEM::PROPER-LIST.

Automatically continuing.
To enable the Lisp debugger set *debugger-hook* to nil.
(%i7) 
===================[cut]============================================

What am I doing wrong?