Frederick,
Here's something you can use to debug this issue. I'm using W3TC 0.9.4 on Wordpress 2.8.2 btw. Loading images via SSL doesn't work with our setup, so the site ends up looking broken.
The CSS file: http://cdn.androidpolice.com/wp-content/themes/ap1/style.css. As you can see, it contains many images with relative paths. For example:
#header {
background: transparent url(images/header_bg_1px.png) repeat scroll 0 0;
height: 124px;
}
Now, in http://www.androidpolice.com/wp-content/plugins/w3-total-cache/pub/minify.php?file=hY_dDoMgDIVfyA692vPwU5WkAqE1zrdfxcVki8kugEPP-QrtjS2DoejY-Dkzpu-j65tfkVE-mmUn7AbV4MiywFjzAjIjFL0Zz3xYHAM6W__mbqyTqegxCZTMwrDFMOHF3FjK-JzEeu2V6wJPE5OnNSA3qP2ZNTTa5HeXX0cKtlxD0dH4Kl9Co1vRF4jYtB20jRbFOsKTOfoGHO1K8lhiOgne0xynmXSJ0YEWvEK_NtY3.css, which I've mirrored here https://gist.github.com/anonymous/51e5bc6dc692f62e89e9 in case it goes away, all these images are rewritten with full paths and https for no reason.
The page I'm accessing is http://www.androidpolice.com without https.
This bug goes back over a year - can you help push out the fix once and for all? This is the last thing preventing me from using Minify CSS in W3.