MarketPress Update may have messed up my cart in FlexMarket?

I use FlexMarket. I'm now getting this error:
Fatal error: Error! MarketPress doesn't have a get_cart_contents method. in /home/dspinner/public_html/wp-content/plugins/marketpress/marketpress.php on line 937
Support is enabled. I have tried turning off Flexmarket with success, however, since my site is configured to it, it is completely wonky when I use FrameMarket, etc. I have emailed the Flexmarket site, with no answer to date. I did try installing their plugin for MarketPress Mojo, but it didn't fix the problems. Can you help?