Hmm, that's odd. Have you tried clearing your cache from Dashboard > Sitewide Settings > Speed Settings?

If that doesn't help, I would suggest making a new ticket in the Superfish support area:

http://www.concrete5.org/marketplace/addons/superfish/support/...

Make sure post your environment info when you open the ticket.

Thanks for taking the time to reply. Yes, I've checked the usual areas.. deleted all files in the cache directory. I've used superfish on every page so the whole site dies when I enable the cache. I bought mega menu and it worked fine with the cache enabled so it's obviously something in the SuperFish installation. I'll lodge a ticket. I thought maybe someone would have a quick suggestion for a fix.