file open error at ftp even the file is not open.....

Hi,

i get the error File open with the fm GUI_UPLOAD while uploading the XML file from FTP server.

What is interesting is that i did not open the file, furthermore i closed all the windows else that sap window,

but still i get the file open error.

We create the xml file when created a new delivery. And this xml file is sent to a bukrs's ftp and they also sent the same xml after some validations done.

When it arrives to our ftp server i make it post goods issue automatically but from yesterday i got the file open error, it was working fine just before today.

What could be the problem?

Hint: Yesterday and previous day files still work fine but files created today are faulty.

Thanks.