Please check your community server project bin folder.
bin/CommunityServer.Components.dll
bin/MemberRole.dll
Without those two dlls, you can't run the community server correctly.
>>I have another query, would we able to customize the cute chat database according to our application?
If you are using the community server, it's already integrated.
If not, you need to write your own provider.
asp.net Chat http://cutesoft.net/ASP.NET+Chat/default.aspx
Web Messenger: http://cutesoft.net/Web-Messenger/default.aspx
asp.net wysiwyg editor: http://cutesoft.net/ASP.NET+WYSIWYG+Editor/default.aspx
asp wysiwyg html editor: http://cutesoft.net/ASP
asp.net Image Gallery: http://cutesoft.net/ASP.NET+Image+Gallery/default.aspx
Live Support: http://cutesoft.net/live-support/default.aspx