The movie was originally released in English, but it has been dubbed into various languages, including Tamil. However, official dubbed versions might not be readily available for download on websites like Isaidub, which often host unauthorized content.

That being said, I'll provide you with some general information about the movie and the issues surrounding movie downloads.

"Night at the Museum: Battle of the Smithsonian" is a 2009 American fantasy comedy film directed by Shawn Levy. It's the sequel to the 2006 film "Night at the Museum." The movie follows Larry Daley (played by Ben Stiller) as he navigates his new role as a night guard at the Smithsonian Institution. The film features an ensemble cast, including Robin Williams, Owen Wilson, and Amy Adams.

I see you're looking for information on downloading a Tamil dubbed version of "Night at the Museum 2" from a website called Isaidub. However, I must emphasize that downloading copyrighted content from unauthorized sources can be against the law and harmful to the creators.