"Another component is already using directory:" -

Ok, there is probably a simple solution to this, but being the proverbial "n00b", it eludes me thus far. Its driving me completely insane.

I've installed Mambo 4.5.2, works fine, installed Gallery 1.5 (This version of Gallery was released on 04/14/2005.) It works ok stand alone also.

Now when I try to install Gallery as a component of Mambo I get the message:

Another component is already using directory: "/home/mysite/public_html/components/com_gallery/"

There is nothing installed there. I've deleted the file, [theres nothing there to delete], and I haven't installed anything previously. I've gone so far as to wipe everything [Just starting out so no data to lose] and just install a clean fresh version of Mambo 4.5.2 and Gallery 1.5. No deal. Exactly the same problem.

Please help. Like seriously. Before I top myself or something! /me rips out hair.
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The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful):
Gallery version: 1.5
Apache version: Apache/1.3.33 (Unix) mod_jk/1.2.8 mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 PHP/4.3.11 FrontPage/5.0.2.2635 mod_ssl/2.8.22 OpenSSL/0.9.7a
PHP version (don't just say PHP 4, please): PHP Version 4.3.11
Graphics Toolkit: Image Magick
Operating system: XP
Web browser/version (if applicable):