Invalid Character During Find Operation

Hello All,
I am encountering an issue where I send a file (for example) named send_to_partner.xml and drop off to partners /In folder. I then go to the /Out folder to get a response with the same name I used in sending, but my issue is that in the /Out folder, there are additional characters that precede the file name such as "4 ". That is a four and a space that precedes the file name. So, step 1 is where I do a Find * for any file name. It shows that it found the file name I sent with the "4 " in front. But the next step is where I do a copy/move and this fails with the error “Error executing Copy from Out folder. Error java.io.IOExcepton: java.io.IOException: FTP Error! Expected 150 but got 550 The system cannot find the file specified.”
The partner who maintains the FTP site says there is no "4 " in the folder. Active Transfer shows a "4 ".