Apache not recognizing a .zip file within document root

Question

I have apache 2.2 running with mod_rewrite as user/group www/www. I'm using the directive

RewriteCond %{SCRIPT_FILENAME} !-f

So that any actual file that exists in a document root is accessible.

There are multiple .zip files in the same directory that are downloadable, one of which is larger than the file that will not download.

You can see what I mean at

http://www.globalmajic.com/c11/GMSINet-Knob-v20-p7.html

There are 3 file download links under 'Support Files' on this particular page, and the last one is the file link that doesn't work.

I also checked permissions and they are exactly that same, as well as ACLS.

Also the file itself was previously available on for download and only recently stopped being downloadable.

Also it only seems to be occurring with certain files that have a particular naming scheme. Here are the file urls

http://www.globalmajic.com/mc_files/8/GMSNETAGauge.zip

http://www.globalmajic.com/mc_files/8/GMSNETNumericLED.zip

http://www.globalmajic.com/mc_files/8/GMSNETInstrumentLibrary.zip

http://www.globalmajic.com/mc_files/8/GMSNETKnob.zip

http://www.globalmajic.com/mc_files/8/GMSNETLED.zip

Has anyone come across something similar to this before? Any help would be appreciated.