Problem uploading file using j2ssh

Hi all,
I am new to this list. I am using open j2ssh for my project. Before building j2ssh into my application, I tried the SftpConnect.java and was able to connect to the remote host and upload files. I am using private key authentication and also password authentication. Everything is fine and was able to upload. When I build it into my application and deployed it , I am able to upload the file but its in a read only format and also I get this error : "packet took too long . disconnected from the remote server". It would be grateful if anybody can help me out in this. 
Thanks in advance, 
shyam