If you used an iPad to record your videos, you will need to connect the iPad to your computer, import the video file to your computer, and then upload it to your application from there. The iPad will not be able to upload the correct file type directly. Here is a link to Apple's support site that has instruction on how to import these files to your computer -
Once you have the files on your computer, you will want to make sure you have the correct file to upload. One way to tell that you have the correct file is that it will be larger that 1-2mb in size. If you are using iPhoto, first create a new folder on your desktop and call it something like "videos". Next, go to iPhoto and click the file(s) so that it is highlighted. Then, then go to the "File" dropdown menu and click "Reveal in Finder", and select "Original File". That will show you the file you need to upload. From there you can either drag that file into the folder you created or make note of it's exact location, and that's where you will need to upload it from into your application.
If you are using iTunes, you should be able to highlight the file, go the the 'file' menu, and select "Show in Finder". That will show you the file you will need to upload to the application.
For more tips on how to upload your videos, click here: Uploading Video, Audio, Documents, and Images