Help with Install Error

Hey all -

I'm having some trouble building and installing matplotlib on my Macbook Pro running OS X 10.5.4.
I don't understand exactly what the errors are trying to tell me...any help is much appreciated!

i686-apple-darwin9-gcc-4.0.1: -framework: linker input file unused because linking not done
i686-apple-darwin9-gcc-4.0.1: Tcl: linker input file unused because linking not done
i686-apple-darwin9-gcc-4.0.1: -framework: linker input file unused because linking not done
i686-apple-darwin9-gcc-4.0.1: Tk: linker input file unused because linking not done
powerpc-apple-darwin9-gcc-4.0.1: -framework: linker input file unused because linking not done
powerpc-apple-darwin9-gcc-4.0.1: Tcl: linker input file unused because linking not done
powerpc-apple-darwin9-gcc-4.0.1: -framework: linker input file unused because linking not done
powerpc-apple-darwin9-gcc-4.0.1: Tk: linker input file unused because linking not done
g++ -arch i386 -arch ppc -isysroot /Developer/SDKs/MacOSX10.4u.sdk -g -bundle -undefined dynamic_lookup build/temp.macosx-10.3-fat-2.5/src/_tkagg.o build/temp.macosx-10.3-fat-2.5/CXX/cxx_extensions.o build/temp.macosx-10.3-fat-2.5/CXX/cxxsupport.o build/temp.macosx-10.3-fat-2.5/CXX/IndirectPythonInterface.o build/temp.macosx-10.3-fat-2.5/CXX/cxxextensions.o -L/usr/local/lib -L/usr/lib -L/sw/lib -L/usr/X11R6/lib -L/usr/local/lib -L/usr/lib -L/sw/lib -L/usr/X11R6/lib -lstdc++ -lm -lfreetype -lz -lstdc++ -lm -o build/lib.macosx-10.3-fat-2.5/matplotlib/backends/_tkagg.so -framework Tcl -framework Tk
ld: in /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/libPng.dylib, file is not of required architecture for architecture ppc
collect2: ld returned 1 exit status
lipo: can't open input file: /var/folders/U8/U8oYQjnOFIi8el0mQQiHaU+++TI/-Tmp-//ccyj53Iw.out (No such file or directory)
error: command 'g++' failed with exit status 1

Thanks
-Adrian