DriveHQ's FTP server supports standard FTP, FTPS and SFTP protocols. I don't see any problem in your DriveHQ account. Please test it with an FTP client program such as FileZilla. You should be able to log on with FileZilla or other FTP client. If not, we can help you trouble shoot it.
Your problem seems to be related with your Java code or your local network connection. Unfortunately we usually cannot troubleshoot custom software code. If you ordered a business/enterprise level subscription, I will try to escalate it to our engineers.