sage install error

[Bruce Meier]

Freebsd 8.2 release

processor amd64

#more start.log
[2012-05-07 01:11:58] Sage version 4.8, released 2012-01-20
Setting permissions of DOT_SAGE directory so only you can read and write it.
Traceback (most recent call last):
   File "/usr/ports/math/sage/work/sage-4.8/local/bin/sage-eval", line 
4, in <module>
     from sage.all import *
   File 
"/usr/ports/math/sage/work/sage-4.8/local/lib/python2.6/site-packages/sage/all.py", 
line 78, in <module>
     import sage.symbolic.pynac
   File "expression.pxd", line 6, in init sage.symbolic.pynac 
(sage/symbolic/pynac.cpp:19189)
   File "expression.pyx", line 145, in init sage.symbolic.expression 
(sage/symbolic/expression.cpp:35722)
   File "function.pyx", line 31, in init sage.symbolic.function 
(sage/symbolic/function.cpp:11736)
ImportError: 
/usr/ports/math/sage/work/sage-4.8/local/lib/python2.6/site-packages/sage/ext/fast_eval.so: 
Undefined symbol "log2"
[2012-05-07 08:23:04] Sage version 4.8, released 2012-01-20
Traceback (most recent call last):
   File "/usr/ports/math/sage/work/sage-4.8/local/bin/sage-eval", line 
4, in <module>
     from sage.all import *
   File 
"/usr/ports/math/sage/work/sage-4.8/local/lib/python2.6/site-packages/sage/all.py", 
line 78, in <module>
     import sage.symbolic.pynac
   File "expression.pxd", line 6, in init sage.symbolic.pynac 
(sage/symbolic/pynac.cpp:19189)
   File "expression.pyx", line 145, in init sage.symbolic.expression 
(sage/symbolic/expression.cpp:35722)
   File "function.pyx", line 31, in init sage.symbolic.function 
(sage/symbolic/function.cpp:11736)
ImportError: 
/usr/ports/math/sage/work/sage-4.8/local/lib/python2.6/site-packages/sage/ext/fast_eval.so: 
Undefined symbol "log2"