This usually happens when you don't have the correct permissions set on the file or the folder.
Do you know what permissions it has set?
I don't use DW for uploading but I believe it has a 'passive upload mode'. Do you have that check box selected?
I checked the permissions on the folder and it is read, write, execute for owner and for all so I can't see that being the problem. The FTP settings for the site are not set to 'passive'.
I have just managed to upload the file using the hosting service's own file manager (FTP) through the web browser and the file works fine so this is definitely something to do with the set up in Dreamweaver. Still can't figure out what though.
The FTP settings for the site are not set to 'passive'.
It should be set to passive. Although in my opinion youre much better off using a stand alone ftp client. I've never personally been a great fan of the inbuilt one but I believe it has been upgraded a few times since I used it about 8 years ago...so it may be better now.
It should be set to passive.
That's not necessarily a good general recommendation. If you are having Firewall problems, then passive FTP is surely the way to go.
And by the way, the DW FTP is all I have ever used....
Notwithstanding those comments, I'm not at all convinced that this has anything to do with user-adjustable FTP parameters. The fact that uploading the file with a 3rd party FTP application suggests that it's definitely something to do with DW, however. If I had this experience, I'd just use the 3rd party FTP application.