minpack_solve error



Could someone please tell me what I'm doing wrong here?
Thank you.

(%i1) load("minpack")$
[snipped loading stuff]
(%i2) flist: [25*sqrt(64*(tr-tf)^2/5625+tf^2/225)/4-135/4,25*sqrt(64*(tr-tf)^2/5625+tr^2/225)/4-165/4];
(%o2) [(25*sqrt((64*(tr-tf)^2)/5625+tf^2/225))/4-135/4,(25*sqrt((64*(tr-tf)^2)/5625+tr^2/225))/4-165/4]
(%i3) varlist: [tr,tf];
(%o3) [tr,tf]
(%i4) guess: [10,10];
(%o4) [10,10]
(%i5) minpack_solve(flist,varlist,guess);
put: argument must be a symbol or a string; found: 'linearalgebra
?-- an error. To debug this try: debugmode(true);

attached is a screenshot with 2D display.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 2D.png
Type: image/png
Size: 8142 bytes
Desc: not available
URL: <http://www.math.utexas.edu/pipermail/maxima/attachments/20111219/e48d99ea/attachment-0001.png>;