Domain Mapping plugin several problems

I have several problems.
Using the plugin locally (with DNS emulations and hosts files all works properly)
> i add the choosen domain to map ( and allways i get "invalid staus". I setted the domain as follow: A
* A
(xxx it is just to hide real ip here)
> on the web server is mapped to the same wordpress doc root
> if i try to disable the dns check (it allow me to add domain as invalid), i relate it to my and then i call in the browser: i have the error: Internal Server Error (as setted up redirect to
> if i disable the the mapping erasing the list of the associated domains to map, work properly. give me the samer: Internal Server Error

Please let me know
as soon as possible

Thanks a Lot