"Could not start transfer"

I'm a freelance editor and have been given access to Filezilla by my customer, a publishing company. Up until now I have been able to download their PDF files for editing in Adobe just by clicking on them, but now I cannot seem to download them -- or Excel files -- at all. I can get to the directory and the files just fine, and when I click on them, I get the regular message saying I'm connecting. But almost immediately I get a message saying "could not start transfer" and the attempt goes into the Failed Transer file. My customer, however, says she can download these files with no problem from Filezilla onto her office computer and has no suggestions for me.

I have checked, and I am using the most recent version of FileZilla.

I hope you can help. I will lose the project if I cannot access the files.

Thanks.