Hello,
Occasionally when importing a video strip into the VSE, the length of the video strip will not match the length of the audio strip. This bug has been noticed on windows (7 and 8) versions of Blender (since 2.73, still active on 2.75a) whereas it doesn't occur on the mac version.
Sample blend file + footage to download here: https://drive.google.com/file/d/0B-hdZ24__KJjNzkzWjhxQTR6b0k/view?usp=sharing
Best