Error - not allowed by the security policy

[Mark]

Hi - no problems running locally on localhost, however when deployed to
host (one&one) I get the following messgage at these lines (two
different files):

<form id="Form2" method="post" runat="server">

Description: The application attempted to perform an operation not
allowed by the security policy. To grant this application the required
permission please contact your system administrator or change the
application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Security error.

[SecurityException: Security error.]
ASP.hotel_admin_aspx.__BuildControlcalOverview() +0
ASP.hotel_admin_aspx.__BuildControlForm2() in
e:\kunden\homepages\25\d85356584\securehosting4u\bookingcentral.co.uk\ho
tel_admin.aspx:16
ASP.hotel_admin_aspx.__BuildControlTree(Control __ctrl) in
e:\kunden\homepages\25\d85356584\securehosting4u\bookingcentral.co.uk\ho
tel_admin.aspx:1
ASP.hotel_admin_aspx.FrameworkInitialize()
System.Web.UI.Page.ProcessRequest() +85
System.Web.UI.Page.ProcessRequest(HttpContext context) +18

System.Web.CallHandlerExecutionStep.System.Web.HttpApplication+IExecutio
nStep.Execute() +179
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&
completedSynchronously) +87

...
..
..
and
..
..
...

<aspanel id="pnCheck" Runat="server">

Same error message, with this stack trace:

[SecurityException: Security error.]
ASP.check_aspx.__BuildControltbCheckIn() +0
ASP.check_aspx.__BuildControlpnCheck() in
e:\kunden\homepages\25\d85356584\securehosting4u\bookingcentral.co.uk\ch
eck.aspx:16
ASP.check_aspx.__BuildControlForm1() in
e:\kunden\homepages\25\d85356584\securehosting4u\bookingcentral.co.uk\ch
eck.aspx:15
ASP.check_aspx.__BuildControlTree(Control __ctrl) in
e:\kunden\homepages\25\d85356584\securehosting4u\bookingcentral.co.uk\ch
eck.aspx:1
ASP.check_aspx.FrameworkInitialize()
System.Web.UI.Page.ProcessRequest() +85
System.Web.UI.Page.ProcessRequest(HttpContext context) +18

System.Web.CallHandlerExecutionStep.System.Web.HttpApplication+IExecutio
nStep.Execute() +179
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&
completedSynchronously) +87


I'd really appreciate any thoughts on this, thanks, Mark