Your test hello world worked for me with STLport STLport-5.0.3, note it did need the DLL for libstlport.5.0.dll to work. Below is my compile commands.
Note, the readme stated that STLport includes must before the normal includes.
-------------- Build: Release in helloworld ---------------
mingw32-g++.exe -Wall -O2 -mthreads -IC:\apps\MinGW_GCC_3.4.5_API_3_8_STLport\STLport\stlport -IC:\apps\MinGW_GCC_3.4.5_API_3_8_STLport\include -c C:\CodeProjects\CodeBlocksProjects\CodeBlocks\CB_SVN_TEST\codeblocks-head-test\codeblocks\src\tests\STLport\helloworld\helloworld.cpp -o obj\Release\helloworld.o
C:/apps/MinGW_GCC_3.4.5_API_3_8_STLport/STLport/stlport/stl/_uninitialized.h: In member function `void stlp_std::vector<_Tp, _Alloc>::_M_insert_overflow_aux(_Tp*, const _Tp&, const stlp_std::__false_type&, size_t, bool) [with _Tp = stlp_std::string, _Alloc = stlp_std::allocator<stlp_std::string>]':
C:/apps/MinGW_GCC_3.4.5_API_3_8_STLport/STLport/stlport/stl/_uninitialized.h:239: warning: '__cur' might be used uninitialized in this function
mingw32-g++.exe -LC:\apps\MinGW_GCC_3.4.5_API_3_8_STLport\STLport\lib -LC:\apps\MinGW_GCC_3.4.5_API_3_8_STLport\lib -o bin\Release\helloworld.exe obj\Release\helloworld.o -s -lstlport.5.0.dll
Info: resolving stlp_std::cout by linking to __imp___ZN8stlp_std4coutE (auto-import)
Process terminated with status 0 (0 minutes, 0 seconds)
0 errors, 1 warnings