We use SSL encryption to secure our website, proxy and software. Do you have the CAcert Root Certificate installed?

No? Not sure? Download it here and permit usage for Websites, EMail and Software. That will save you from importing a dozen differnt certificates. Check that the SHA1 displayed is

DB:4C:42:69:07:3F:E9:C2:A3:7D:89:0A:5C:1B:18:C4:18:4E:2A:2D

Just use https://krdwrd.org to access the site from now on, and you will not be bothered with this message.