I received files via text messages in my phonefrom a friends Dropbox. How do I get them into my Dropbox to open and view them?

I got 3 text messages in my phone, and each had video files with the word Dropbox in the link, and my friend said he used Dropbox to send them. I opened one successfully in my phone messages, and then forwarded all 3 to my email, so the files were in the computer, but still couldn't open the other 2. I kept getting an error message saying Dropbox couldn't find the files, and I can't figure out how to get them in Dropbox. Thanks for your help!