Catch 22 Default Apps

[Clark]

I am in an difficult spot, when I use default applications (setup) in 
System Settings to set email and Firefox it doesn't seem to work, so I 
select the Help menu, this tells me there is no documentation for this 
function, next I select the on line help, it doesn't give me a www 
address, it tries to connect me (very nice if it did) but as it can't 
find Firefox it kindly tells me so "can't find Firefox. 
Can someone help me break out of this cycle?

Clark.