Captured footage always underexpose

[freedom1029]

When I shoot with my Panasonic 3CCD GS250 I make sure that my white balance is correct(manual white balance) as well as my exposition and everything looks good in my viewfinder and LCD. However when I capture my footage via Premiere or other software, my video is always under exposed. Why is that and how can I correct the situation?
Thank you,
Eric