Reason: Your database is in a folder where there is no write/change permission.
Resolution:
If using Windows 2000 - IIS5- the {Server}\ASPNET User Account must have Read, Write, and Change Control of the Folder where database resides
If using Windows 2003 - IIS6- the NETWORK SERVICE User Account must have Read, Write, and Change Control of the Folder where database residesGiving EVERYONE account full control will solve your problem too but Never do that as it will expose your system to external attacks within network.