The fork errors are bugs in the sh.exe (a shell utility provided with minGW) you are using under vista. See Aarons site for the exact problem and a resolution.
I don't have Vista at the moment and with my time limited I don't really plan on switching anytime before the first service pack
The earlier problems you had are missing files in your minGW installation (probably a path problem but only you can really diagnose that one to be honest).