There are a number of known problems in current GCC when compiled for windows, relating mostly to exception handling with DLLs in use. (There are also a lot of backwardly-incompatible changes in recent GCC that make it more demanding of strict standards compliance in C++ usage than it used to...
Hello profroopchan.
I think your system administrator must have a misunderstanding. If there are trojans or even just corrupt files on any mirror site, they will fail either the md5 checksum test or the setup.ini digital signature check; setup.exe will refuse to install an invalid or tampered...