I am having the exact same problem. The web config has this which does not have explicit information about the server, etc. :
<connectionStrings>
<add name="ClubSiteDB" connectionString="Data Source=.\SQLExpress;Integrated Security=true;AttachDBFileName=|DataDirectory|clubsite.mdf;User Instance=True" providerName="System.Data.SqlClient"/>
<remove name="LocalSqlServer" />
<add name="LocalSqlServer" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true" providerName="System.Data.SqlClient" />
</connectionStrings>
All this stuff is generated when the site is created and the databases are created in the admin. The connection seems to be fine in the development environment but when run straight from a browser it throws this error.
Failed to update database "C:\INETPUB\WWWROOT\COMMUNITY\APP_DATA\ASPNETDB.MDF" because the database is read-only.
I have spent allot of time attempting to give rights to aspnet and the anonymous user etc., but nothing has seemed to help. I do know of any tools to grant rights from the SQL 2005 express database.
If you know what should be in these attributes to resolve this error please let me know.
Thanks