You did not give us enough info...
Is this the form URL you meant to give us?
(To me this does NOT look like a ColdFusion error, unless they've neatened it up since CF 5. This look more like an Apache error.)
Does a normal test.cfm page (maybe printing the date) work? (i.e. is ColdFusion configured and functional?)
Can you give us the emailer.cfm code so we can see where you are a calling modules and how?
Do you have includes that might have nested module includes?