failure with python setup.py build

Hello, I would like to know what I can do to fix this problem.

Administrator@...2351... /cygdrive/c/downloads/matplotlib-0.98.3 : python setup.py build

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============================================================================

BUILDING MATPLOTLIB
           matplotlib: 0.98.3
               python: 2.5.2 Stackless 3.1b3 060516 (release25-maint, Oct
                       1 2008, 19:33:07) [GCC 3.4.4 (cygming special, gdc
                       0.12, using dmd 0.125)]
             platform: cygwin

REQUIRED DEPENDENCIES
                numpy: 1.2.0
            freetype2: 9.18.3

OPTIONAL BACKEND DEPENDENCIES
               libpng: 1.2.12
Traceback (most recent call last):
File "setup.py", line 125, in <module>
   if check_for_tk() or (options['build_tkagg'] is True):
File "/cygdrive/c/downloads/matplotlib-0.98.3/setupext.py", line 841, in check_for_tk
   explanation = add_tk_flags(module)
File "/cygdrive/c/downloads/matplotlib-0.98.3/setupext.py", line 1084, in add_tk_flags
   result = parse_tcl_config(tcl_lib_dir, tk_lib_dir)
File "/cygdrive/c/downloads/matplotlib-0.98.3/setupext.py", line 946, in parse_tcl_config
   tk_lib = tk_vars.get("default", "TK_LIB_SPEC")[1:-1].split()[0][2:]
IndexError: list index out of range
Administrator@...2351... /cygdrive/c/downloads/matplotlib-0.98.3 :