I sure,"这次会议在2010年冬天举行" is correct. 这次会议（subject主语）+在2010年冬天（adverbial 状语+举行（predicate谓语）It emphasizes 在2010看冬天。在means in, at ,on ,etc. in Chinese .Such as,在冬天，在9点，在早上，在屋里，在车内，在心里…… You also say 在2010年冬天举行这次会议.

“这次会议在2010年冬天举行”是正确的。我们通常在地点，时间前面用“在” we usually use“在”before the time or the places.

just remember that chinese is a typical analytical language, where it means a sentence is allowed to be stated in a highly flexible way. normally we express a sentence in an order of SVO, that is, subject+verb+object. but this’s not necessarily rigid. e.g. 今天你上了物理课吗？（SVO）we can also say：今天物理课你上了吗？（OSV）（c.f. 我把车卖了。SOV with a an auxiliary verb 把） dizzying？actually it's simply & cool, for i guess most of the human languages will get to be analytical, just as the english language did in the past three hundred years.

sometimes we may say ‘‘不如2010年冬天举行这次会议吧（expressing a wish）’or ‘2010年冬天将会举行这次会议（stating a decision or a schedule）’or ‘2010年冬天举行了这次会议（stating an event that had happened）’, where the subject and the preposition 在 can be omitted. or we may say ‘2010年冬天举行这次会议很适合’to state a judgement.