I just downloaded Dawnguard, loaded up wrye bash and a window pops up which says "Missing string localization files" and it says this will cause CTD's. In the list, the dawnguard esm is pink and if I activate it, it is red. When I go into the game with Dawnguard loaded, it does crash my game (although not sure if this is due to a mod conflict) but it probably has to do with this issue. How do I fix it>>>

not sure been waiting for an answer all day and on all the forums same thing is happening to me and others using Wrye Bash, however, I have seem to been able to run Skyrim through Steam, thats how I eventually got it to boot up correctly, then I exited and booted it back up with SKSE and it worked fine, however, i saved every two seconds and after extended play I eventually did have crashes soooo I dont know this svcks lol

I can load up the game and get into it, but it crashes within a minute.

Wrye Bash can't yet look inside .bsas for localized strings. Since Dawnguard's strings are inside Dawnguard.bsa, Bash doesn't know they exist, thus the error. If you want Bash not to worry about it, just take the strings from the .bsa and move them into Data/Strings.

Your crashing is unrelated to this issue.