I just tried importing to my inventory from a .csv file, and after double checking that all the headers were correct and there was zero formatting, I still get this error:

Error: The server encountered a problem trying to import your file. Please check that it is a plaintext csv file and try again.

I also tried saving in different .csv typed formats (macintosh, ms-dos, windows) to no avail. Any ideas?

Could you send us the file at support@deckbox.org, we'll take a look what is wrong. It might be an encoding issue.

Well, I fooled around with copying the data differently and got this to work. Excel was saving formatting for some reason and I had to manually adjust it not to within the .csv file.