System.Net.WebPermission

[Mohamed Refaat]

i'm using infopath with sharepoint portal
the infopath form calls a web service in this manner

IAppCreate.IAppCreate wsObj = new IAppCreate.IAppCreate();
wsObj.PreAuthenticate = true;
wsObj.Credentials = new System.Net.NetworkCredential
("username","pwd","domain");
wsObj.Url = "Webservice url";
wsObj.Save(parametr);


when i published this form to the sharepoint server i
always recieve this error
"System.Net.WebPermission"