Dynamic CSS/JS Files Not Working

[eluser]Bluemill Media[/eluser]
This does not work: <link href="/shop/{$StoreInfo.Slug}/styles/main.css" rel="stylesheet" type="text/css" />

This does work: <link href="/system/app-shop/Red/styles/main.css" rel="stylesheet" type="text/css" />

(Please note that {$StoreInfo.Slug} outputs as the name of the user, e.g. 'lorren'.

Regarding the query based URL, I've tried that during debugging and it didn't give me a solution. Also, keep in mind that these URLs are going to be used by store owners/template designers, so the URLs need to be pretty and user-friendly.

Also, it's important to note that in using the developer toolbar I can 'CSS > View CSS' and it takes me directly to the stylesheet with all styles displayed, but they're just not being applied. Simplified: I'm pointing to the correct file with every URL type...the browser just isn't reading the styles in the file through...to make matters even more odd, Firebug reports the pages as 404s in the NET panel...

I'm at a total loss.