LIBPQXX nmake problem!!!!

Hi...

I am trying to nmake the libpqxx.mak file, in order to work with the 
libpqxx library...I am using MVC7 (.NET) that is the compiler I am 
suppossed to used...I followe the install instructions for Windows (win32 
folder)....but I am having the following error:

../include\pqxx\result.h(303):error C2511:'bool pqxx::Result::Field::to
(std::string&) const' : overloaded member function not found 
in 'pqxx::Result::Field'    ../include\pqxx\result.h(91):see declaration   
of 'pqxx::Result::Field'

../include\pqxx\result.h(315):error C2511:'bool pqxx::Result::Field::to
(const char*&) const' : overloaded member function not found 
in 'pqxx::Result::Field'    ../include\pqxx\result.h(91):see declaration   
of 'pqxx::Result::Field'

NMAKE : fatal error U1077: '"C:\Program Files\ Microsoft Visutal 
Studio .NET\VC7\Bin\nmake.exe"' : return code '0x2'

NMAKE : fatal error U1077: '"C:\Program Files\ Microsoft Visutal 
Studio .NET\VC7\Bin\nmake.exe"' : return code '0x2'
Stop.


HELP!!!!!!!!