"there was an error downloading your file"

Sounds like you are using the web interface, whereas normally the files/folders are already on your computer.

Clearly Heather S. has moved on, and I wish her well.  I choose to comment now because this is the first post I saw when I Googled Drobox "there was an error downloading your file".

Dropbox can be used without having an account, which is to say that other folks can share links or directories with you and you just go there and get some content.  Of course Dropbox tries to get you to log in, but you can still say "no thanks".  There is  a "web interface".

This is good for people like me who don't want to install a Dropbox client, and who insist on using Linux as their first and ONLY operating system and so who are used to clients for the Win/Mac world not working.  

In my case, Google Chrome (Specifically 38.0.2125.111 Built on Ubuntu 14.04 running on Linux Mint 17, 64-bit) simply stopped working with Dropbox (got download errors on every file I tried) ... who knows why.  

I switched to Firefox (Specifically Firefox 33.0 "Firefox 1.0 for Linux Mint") and downloading works again.  I would recommend that every user, on every OS always keep a couple of browsers around and try the alternate browser trick whenever having problems with a web-site.  As security inevitably "improves" on the web, browsers will break.

I had the same issue. I installed the dopbox client in my pc and selected to download that folder only.

I got the file without any error...

I have also the same problem.