It's not a practise to install web site under the folder that you used. To install MonoX properly please put the MonoX install package to the "C:\inetpub\wwwroot\YourMonoX" folder, extract it, set the folder permissions(have you set it in your previous MonoX installation?), create an empty database and start MonoX install wizzard. When you start MonoX wizzard, all permissions should be set as shown in attached image.
Let us know if that fixed your issue,