I am trying to import a png sequence into After effects CS5. It is importing a completely different file! I have tried renaming the file, and re-creating the file, but it still imports another, completely different one. The names aren't even similar. Any one else had this happen? It never happened to me with earlier versions of AE.
You have enabled "Force Alphabetical Order" in the import dialog? Just a guess, but that would cause other image content to appear within the sequence. If that is not it, we need more info on operating system, how the files are actually named and where they are stored...
Is the file that's being mistakenly imported in the same folder as the one that you're trying to import? What are the names and path of the file that you're trying to import and the file that's being imported?
How, exactly, are you doing the import? Screenshots would help.
What operating system?
Have you installed the After Effects CS5 (10.0.1) update?