W3TC conflicting with WP E-Commerce Product Downloads

Hello:

I recently installed W3 Total Cache, and it has helped noticeably with my site’s speed, just as advertised. However, it has caused some conflicts with WP E-Commerce, forcing me to deactivate it until I find a solution.

Many of the products we sell include digital downloads (in the form of zip files ranging from 30-120 mb) attached to individual product variations in WP E-Commerce. But with Total Cache activated, the digital download portions of my customers’ purchases fail. With Safari, they end up downloading a very small (or zero K) zip file that produces a “decompression failed” error when you try to open it. In other browsers, they apparently end up on a nonexistent webpage. When I deactivate Total Cache, the problem disappears.

I’ve tried various enable/disable combinations of the Total Cache plugin to no avail. Any ideas? I saw a reference elsewhere to increasing php memory allocations, but I’m a newbie, and I didn’t follow how to make the change. Are there options I can disable on the plugin to allow product downloads to work properly?

Thank you very much!

http://www.paradiseofbachelors.com

http://wordpress.org/extend/plugins/w3-total-cache/