(0x8102006D): The security validation for this page is invalid

As usual, when you try to install the whole thing in IIS you always get errors from the web services. Normally this errors are related with security, and normally you spend more time trying to figure out WHY than developing the code. It is part of the new OS's bussines, security.

This issue normally comes when you are not able to do a call from the web browser, to avoid these problems you just need to set your SPWeb object as xxx.AllowUnsafeUpdate = true, so looking my previus code we will add the line in red.
...
SPWeb parentWeb = siteCollection.OpenWeb();

SPWebTemplateCollection Templates = siteCollection.GetWebTemplates(Convert.ToUInt32(LCID));
SPWebTemplate _sptSiteTemplate = Templates[_iSiteTemplateNumber];
if (parentWeb.Webs[_sSiteURLRequested].Exists)
{
parentWeb.Webs.Delete(_sSiteURLRequested);
}

parentWeb.AllowUnsafeUpdates = true;
parentWeb.Webs.Add(_sSiteURLRequested, _sSiteTitle, "", Convert.ToUInt32(1033), _sptSiteTemplate, false, false);
...

Site Creation on Sharepoint 2007

The only way to create a site remotely is developing your own web service on the main Sharepoint 2007 server, just because you will need to use Microsoft.SharePoint(Microsoft.SharePoint.dll) and Microsoft.SharePoint.Search(Microsoft.SharePoint.Search.dll).

What I have developed is a plain class. This class will be the one in charge of doing the job by creating the site.

I attach the code of the class so after that you can call this class from your own web service:

-------------------------------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;

namespace SiteManager
{
public class SiteManager
{
public enum LocalID { EnglishUK = 2057, EnglishUS = 1033, SpanishTraditional = 1034, SpanishModern = 1034, French = 1036, Italian = 1040, GermanGermany = 1031 };

public static bool CreateSite(string _sParentSiteURL, string _sSiteURLRequested, string _sSiteTitle, int _iSiteTemplateNumber, LocalID LCID)
{
bool _bResult = false;

try
{
using (SPSite siteCollection = new SPSite(_sParentSiteURL))
{
SPWeb parentWeb = siteCollection.OpenWeb();

SPWebTemplateCollection Templates = siteCollection.GetWebTemplates(Convert.ToUInt32(LCID));
SPWebTemplate _sptSiteTemplate = Templates[_iSiteTemplateNumber];
if (parentWeb.Webs[_sSiteURLRequested].Exists)
{
parentWeb.Webs.Delete(_sSiteURLRequested);
}

parentWeb.Webs.Add(_sSiteURLRequested, _sSiteTitle, "", Convert.ToUInt32(LCID), _sptSiteTemplate, false, false);

_bResult = true;
}

}
catch (Exception ex)
{
_bResult = false;
}

return _bResult;
}
}

}
-------------------------------------------------------------------------------------------


In order to call this class you will need to create your own web service, and it should looks like something like this:


-------------------------------------------------------------------------------------------
using System;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;

[WebService(Namespace = "http://sheep/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]
public class Service : System.Web.Services.WebService
{
public Service () {

//Uncomment the following line if using designed components
//InitializeComponent();
}

///
/// Description.
///
/// Description
[WebMethod]
public string WebServiceDescription() {
return "Site Mangnager v1.0";
}

[WebMethod]
public bool CreateNewSite(string _sParentSiteURL, string _sSiteURLRequested, string _sSiteTitle, int _iSiteTemplateNumber, SiteManager.SiteManager.LocalID LCID)
{
bool _bResult = false;

try
{
_bResult = SiteManager.SiteManager.CreateSite(_sParentSiteURL, _sSiteURLRequested, _sSiteTitle, _iSiteTemplateNumber, LCID);
}
catch (Exception ex)
{
_bResult = false;
}

return _bResult;
}

}
-------------------------------------------------------------------------------------------

The web service should look like this: