thanks for the suggestion.
i've uninstalled wxWindows-2.4.2 and reinstalled it again.
but when i try to build stc lib, it still gives me the same failure message.
$ mingw32-make -f makefile.g95 FINAL=1 UNICODE=0 WXUSINGDLL=1
g++ -c -DWINVER=0x0400 -D__WIN95__ -D__GNUWIN32__ -I../../../lib/mswdll -I../../../include -I../../../contrib/include -I../../../src/regex -I../../../src/png -I../../../src/jpeg -I../../../src/zlib -I../../../src/tiff -D__WX__ -DSCI_LEXER -DLINK_LEXERS -I../../../contrib/src/stc/scintilla/include -I../../../contrib/src/stc/scintilla/src -I. -I../../../contrib/include -DSTRICT -DHAVE_W32API_H -D__WXMSW__ -D__WINDOWS__ -Wall -O2 -fno-rtti -fno-exceptions -DWXUSINGDLL=1 -o stc.o stc.cpp
C:/DOCUME~1/patrick/LOCALS~1/Temp/cccDbaaa.s: Assembler messages:
C:/DOCUME~1/patrick/LOCALS~1/Temp/cccDbaaa.s:307: Error: symbol `_D' is already defined
c:\MinGW\bin\mingw32-make.exe: *** [stc.o] Error 1