Upload files via FTP

I don't understand your question.  In an FTP listing, the only thing you will see is the listing of the file names.  How are you expecting to see 'data, images or file content'?

When I up load a file, say readme.txt . The file size is 4.09 Kb, however, it appears on the server side as 0 Kb. My images are another example. They are 44.9 Kb, but after uploading they are 0 Kb

Are you refreshing your file listing on the server?  Sometimes the file sizes don't show correctly until you do.

Yes I am

That is kind of odd.  If you attempt to download those files to another directory (so you don't erase your original files), are they still 0 bytes?

Created test directory, and uploaded files. Flashobject (*.swf) are 0 bytes, and some are not complete in terms of size

I understood that.  What happens if you try to download them again?

The results are the same. When I upload one file at a time it might upload the complete file, or may not

I don't have enough info to help you.  You can click on "Request Attention" above and see if someone can.

Issue remains the same, I am working with web site host to see were the FTP up load error  comes from

Is that your own server? Or you rent/bought a space somewhere?
Try also Firefox with addon FireFTP:
https://addons.mozilla.org/en-US/firefox/addon/fireftp/

If it is a rented space try to speak with the administrator of the server.
Did you try to upload also http ?

If it is yours, what OS do you have on server?
Do you get any other errors?
Could you monitor the transfer?