500 Internal Server Error when attempting to 'Sync Offers'

[peteheaney]

Wordpress 3.5.1
Official Topspin WordPress Plugin 4.0.9.1

When clicking the 'Sync Offers' button to cache the offers, it hangs for a while then gives a 500 Internal Server Error. Afterwards, it still says "Last Cached: Never".

The 'Sync Artists' and 'Sync Products' buttons work as expected.

Note that the max_execution_time in php.ini is set to 2 mins, and it doesn't hang for as long as that, so I don't believe PHP is timing out.

This problem is only occurring on my production server (MediaTemple dv 4.0). I have installed the plugin on my dev server (WAMP) and it works correctly.

I have tried installing the plugin on my production server both on my existing site (WP 3.5.1) and on a completely fresh installation of Wordpress 3.5.1. The problem occurs in both cases.

After attempting to sync the offers, if I check the 'View Offers' page, some, but not all, of the offers are displayed, suggesting that it is managing to pull in at least some of the data. A timeout of some kind?

Any help would be appreciated.