Cannot get download button to show up on purchases

[Xena]

If it's not one thing, it's another LOL
I cannot get my downloads to work, no matter what I do. As far as I can see I have everything set up correctly yet a purchased product yields no download link at all. Worst part - it used to work before I upgraded the cart :/
My entire site contains downloadable content only (if that makes a difference).

In my attributes, I have Option Name: Download (Radio button) and Option Value: Zip File.
All zipped files are in the download folder and are appearing with a green icon.
I have Expiry Days set to 0 and Maximum download set to 10.
Used for display purposes only: No.
Attribute free when product is free: Yes.
Default attribute to be marked selected: Yes.
Apply discounts used by product special/sale: Yes.
Include in base price when priced by attributes: Yes.
Attribute required for text: No.
Paypal order status is set to Delivered [3].
The Add To Cart Box on tpl_product_info_display.php is unchanged.

I don't know where else to look. Can anyone help me please?

[lat9]

What are your settings in Configuration->Attribute Settings for the first 8 download-related settings.

The purchase yields no download link, but do you get the notice that "Downloads are not available until payment is confirmed"?

Are there any debug-log files present in your /logs directory (for v1.5.1+) or /cache directory (for earlier versions)?

[Xena]

Enable Downloads true
Download by Redirect true
Download by streaming false
Download Expiration (Number of Days) 0
Number of Downloads Allowed - Per Product 20
Downloads Controller Update Status Value 4
Downloads Controller Order Status Value >= lower value 2
Downloads Controller Order Status Value <= upper value 4
Enable Price Factor true
-------------------
No notice of any kind. Payment is marked as delivered on invoice and on account page.
-------------------
There's a couple of old parse error logs (which are no longer relevant), and the following ...
[16-Mar-2014 06:04:08 America/Chicago] PHP Warning: filesize() [<a href='function.filesize'>function.filesize</a>]: stat failed for /home/shopwick/public_html/wicked21/download/Z-XmasPT.zip in /home/shopwick/public_html/wicked21/includes/templates/template_default/templates/tpl_modules_downloads.php on line 41

I don't have an override in Wicked21 (name of template) and the default file hasn't been changed in any way.
**EDIT** The reason for that error is that file does not exist anymore.