CREATE DATABASE permission denied in database 'master'

[casper]

Hi,

I use asp.net 2.0 and VWD (and sqlserver 2005 express) on windows 2000 sp4..
Starting from VWD, it works.
Starting from the browser, the code below produces this error:
CREATE DATABASE permission denied in database 'master'.
An attempt to attach an auto-named database for file C:\Documents and
Settings\Administrator.PEN1800\My
Documents\testfromc\App_Data\WroxUnited.mdf failed. A database with the same
name exists, or specified file cannot be opened, or it is located on UNC
share.
<form id="form1" runat="server">
<div>
<asp:SqlDataSource id="SqlDataSource1" Runat="server"
ProviderName="<%$ ConnectionStrings:WroxUnited.ProviderName %>"
ConnectionString="<%$ ConnectionStrings:WroxUnited %>"
SelectCommand="SELECT * FROM News">

</asp:SqlDataSource>

<aspataList ID="DataList1" Runat="server"
DataSourceID="SqlDataSource1"
RepeatDirection="Vertical" RepeatLayout="Flow" >
<ItemTemplate>
<div class="newsItem">
<span class="newsTitle"><%#Eval("Title")%></span>
<span class="newsDate"><%#Eval("DateToShow", "{0:dd MMM
yyyy}")%></span>
</div>
<span class="newsContent">
<asp:Image style="float:right" ID="NewsImage"
Runat="server"
ImageUrl='<%# Eval("PictureURL", "~/NewsImages/{0}")
%>' />
<%#Eval("Description") %>
</span>
</ItemTemplate>
</aspataList>

</div>
</form>
The app_data directory contains wroxunited.mdf. and has the right
permissions (IWAM_myserver has full control)

What's the problem here?
Tnaks for help
Casper