UNIX script problem ..Plz help ASAP

Hi folks,
I have written down a UNIX script which actually FTP the file to other server. What is happening now , this script is not working only for 1 server , as it is working for 32 different FTP server .

In this particular server , we are getting message �FTp:550 access denied� but when we see job log , we can see its login in the server successfully but when the script execute the line to transfer file from our UNIX box to their UNIX box .. it shows this message ....

I see the rest job which are successful they show the message �OPEN data connection for Ascii files � , this script is failing here ..What could be the problem ?

As it is the same script which is working for rest of 32 servers .

One more thing when we manually login to there server, and use put command manually .. its transferring the file .. but its failing in ftp script
Please help me ASAP in this regards.
Thanks

Can you post the script and give more information about the OS on the source and destination servers?