ok, I found a solution myself...
Maybe it helps if you have simular Problems.....
I don't know what causes this mistery but it can be solved by sending
a unique Identifier with the QueryString.
For example:
Instead of sending:
My.aspx?name=Rudi&age=12
I now send:
My.aspx?name=Rudi&age=12&UniqueId=1
If the same adress is called an other time again than i Call it with
My.aspx?name=Rudi&age=12&UniqueId=2
My.aspx?name=Rudi&age=12&UniqueId=3
and so on......
On Client side creating the UniqueId by using the Date Funktion
var actualDate = new Date();
window.open("My.aspx?name=Rudi&age=12&UniqueId='+actualDate.getTime(),'','');
so with every call the URL looks different and this seams to solve the problem......
Seems that sending the same URL twice causes the Trouble.........