Wierd files in site ftp root

[maffp]

Hi!

I've just upgraded a site from static html to dynamic php with a custom CMS system. Just now I've just noticed that i've got some wierd files in my ftp root folder.

Two are core.**** (*s = numbers) files (each 36.9MB!)

One is called ".pureftpd-upload.4600388e.15.4402.2f61c688" which refuses to be deleted (or even renamed) because of a "550 Prohibited file name" error

Any ideas?

Thanks.

[Mittineague]

I have a "core" file in my WP install folder that's been there since the last time I used the host's "one click" install to upgrade. Most of the file's contents are not readable in a text editor, but my guess is that it's a sort of compressed "back-up" of the older version (or maybe the newer?) that holds the schema to create the database and most likely directory structure etc.
As for the "550" error I had to search, but I found this

The server won't let you delete the file, because it is a leftover from a failed upload attempt. This is no bug in SmartFTP. You need shell acess or talk to the server admin to delete the file.

[maffp]

Well I don't have wordpress but i was wondering if it's some sort of temp. file which is being created because of some poorly written php?