Again I ran into problems with 1and1 hosting today. When I asked about having AJAX problems on their server, this is their answer:
“Thank you for contacting us.
I would like to apologize because I really have no idea with regards to
scripting and it is not part of our support anymore. I will just give
you the link regarding the AJAX tutorial, I hope this can help you.
Can 1and1 really call this support???
Jonswain's Weblog 
Agreed. I helped migrate two customers’ accounts from 1and1 to ASmallOrange last year mainly because 1and1 provides useless tools that only appeal to amatuer programmers whereas low level controls, such as Apache handlers, MIME types and certain MySQL related tasks are either extremely clumsy, or plain non-existant.
[…] Read about it here. […]
I had this problem 2-3 years ago when trying out the original beta of ms ajax. Their “support” then was just as useful as it is now… three years and no adoption of this useful technology.
I doubt they’ll upgrade to .net 3.5 either (which happens to have ajax built in 😦 )
WARNING to all that might use 1and1.
Canceled an account with them last year…. they told me i had a credit to my on account….but afterwards billed difference of credit to a balance unknown to self… $3.64 outstanding…. they sent it to collections without telling me…Charged an additional $18.50 to $3.64……!!! Just spent 2 hours sorting our with credit agency…. 1and1 seems to be an automated cash machine that will rip you off and cause all sorts of problems…I have been trying to cancel account for over 2 yrs…..!! Unbelivable!