Here might be a cure. This really drove me nuts last night. My first ajax code was working fine, then I found another place where I can use ajax. But the second code was throwing xml-errors. So I reduced the code to a minimum to get any response at all. Nothing! Even my first code wasn't working anymore. Same errors.

Finally I tracked down the error to some modules I installed between writing code 1 and code 2. These modules were in a bad shape, means they had additional lines/blanks after the closing php-tag.

After removing additional lines/blanks everything was working fine again. Felt like an idiot afterwards.

So please dear co-module-developers, review your code and make sure that the php-files are in a good "shape".

Just wanted to share my observations.

I had the same problem with xajax. Blank spaces or lines after php close tag was the last thing I would imagine for this issue.

Great tool xajax class, but everyone that want to use it should be aware about this clue.