Can't tell about 1.46... I've only used 1.45 so far. That one, however, compiles just fine out of the box.
Without knowing the version of your gcc and at least some of the error messages, it's impossible to tell what's going on, too.
Two possibilitites I see are:
a) Maybe you're using the wrong projectfile to build it, and the error messages are because MSVC commandline options are fed to gcc
b) Maybe you're using a very new version (4.3/4.4) of gcc. The newest versions are very strict regarding standard compliance which sometimes causes problems with code that would compile fine with older compilers.