I get this error:

Fatal error: Call to undefined method SimplePie::set_feed_url() in /.../public_html/modules/mod_jw_srfr.php on line 89

I also got this problem...
on my local-server everything was ok, but on the web-server this error appears

Fatal error: Call to undefined function: set_feed_url() in /var/www/web3/html/cmp/modules/mod_jw_srfr.php on line 89

but what is the problem, i don't have changed code or something?

no problem anymore...
i have to say, that i was testing different rss-readers for a study project and had installed different readers at same time
after re-ordering the modules, i recognized that there was no error anymore and now feeds are displayed