Error Upon FTP

I recently set up a new domain on my DH account. (I have several domains on the account already.) The domain’s nameservers have not been changed yet, but I was trying to upload, via FTP, the site content by connecting to

Transfer went well for a while, but then, before I could get all the content uploaded, I got the following error: Error -135: socket write error. I dropped the connection and tried again, but got the same error.

I thought maybe it had something to do with the file size, so I connected to another domain I have with DH that uses a different user and I was able to upload the same files without error.

Does anyone know what this error means and how to correct the problem? TIA.