Make sure this is false in Web.config and/or user.config
<add key="UseFoldersInsteadOfHostnamesForMultipleSites" value="false" />
since your root site is not in the root but in a virtual directory "Community" it is not possible to use folder based child sites so this setting needs to be false, if it is set to true it can cause this problem as you describe.
Hope it helps,
Joe