Problem with upload

Hello.
I'm trying to upload files to my server, but for every file i'm uploading, i'm getting 1 or more 550-errors.

I think the files are uploaded correctly but the errors makes me uncertain if anything is alright.

I'm getting this error with SmartFTP, but not FileZilla. It's too bad, because i've always used SmartFTP so i really don't wanna shift to FileZilla.

Here's my log:
[16:52:56] Remote file exist check: "testfile.txt".
[16:52:56] TYPE I
[16:52:56] 200 Type set to I
[16:52:56] SIZE testfile.txt
[16:52:56] 550 testfile.txt: No such file or directory
[16:52:56] File size check (SIZE) failed. File not found or permission denied.
[16:52:56] TYPE A
[16:52:56] 200 Type set to A
[16:52:56] PASV
[16:52:56] 227 Entering Passive Mode (195,249,40,189,184,244).
[16:52:56] Opening data connection to 195.249.40.189 Port: 47348
[16:52:56] STOR testfile.txt
[16:52:56] 150 Opening ASCII mode data connection for testfile.txt
[16:52:56] 0 bytes transferred. (0 bytes/s) (31 ms)
[16:52:56] 226 Transfer complete.
[16:52:56] MDTM 20070903145245 testfile.txt
[16:52:56] 550 20070903145245 testfile.txt: No such file or directory
[16:52:56] PASV
[16:52:56] 227 Entering Passive Mode (195,249,40,189,184,245).
[16:52:56] Opening data connection to 195.249.40.189 Port: 47349
[16:52:56] LIST -aL
[16:52:56] 150 Opening ASCII mode data connection for file list
[16:52:56] 981 bytes transferred. (59,8 KB/s) (16 ms)
[16:52:56] 226 Transfer complete.
[16:52:56] Transfer successful.

Hello ..

You can ingore these errors. They do not affect your transfers.

Regards,
SmartFTP