If you're using a modpack then it's the modpack's responsibility to make sure end users can use 1.5.2 properly (ie. package our libraries with their pack, it's perfectly legal). If not, then as Lex said, either stop using 1.5.2 because we don't support it anymore, OR fix your own problems using the help provided in the EAQ. 1.5 is EOLed, we're already starting the 1.7 update.