Have yoou updated the files

include/config.php
cgi-bin/uu_default_config.pm

?

Disable upload progress bar, then try uploading a video and see it that works.

http://docs.buyscripts.in/Disable_upload_progress_bar

If upload works fine after progress bar disabled, you need to reconfigure progress bar

http://docs.buyscripts.in/Enable_Upload_Progress_Bar