I finaly resolve my problem. Now everything is working perfectly.
SOLUTION:
In fact it was my solution maybe not for all of you that encounted same problem but if it could help others, so much better, here what I did to succeed my registration of AD ADWARE 2007 PLUS
Not only as prescrybed by Lavasoft support team you have to disconnect or close the FIRE WALL before to ask for the registration but ALSO you must close any ACCELERATOR SOFTWARE if you are using this kind of tool. The one i am using and provided by my internet provider is named SPLIT STREAM (in fact using this company to which belong aforesaid software). After having closing the latter the registration was made successfully , then no more message received like ....THE SERIAL KEY YOU ENTERED APPEARED INVALID.
Good success to others that have encounted same problem. This is my contribution.
Rayal.